The effects of neuromuscular electrical stimulation at different frequencies on the activations of deep abdominal stabilizing muscles.

BACKGROUD: Low back pain is associated with transversus abdominis (TrA) dysfunction. Recently, it was proposed that Neuromuscular Electrical Stimulation (NMES) could be used to stimulate deep abdominal muscle contractions and improve lumbopelvic stability. OBJECTIVE: The purpose of this study was to determine the optimal stimulation frequency required during NMES for the activation of deep abdominal muscles. METHODS: Twenty healthy volunteers between the ages of 24 and 32 were included. The portable research-stimulator was applied using a 10 second contraction time, and a 10 second resting time at 20 Hz, 50 Hz, and 80 Hz. Changes in muscle thicknesses were determined for the TrA, obliquus internus (OI), and obliquus externus (OE) by real time ultrasound imaging. RESULTS: Significant thickness increases in the TrA, OI, and OE were observed during NMES versus the resting state (p < 0.05). Of the frequencies examined, 50 Hz NMES produced the greatest increase in TrA thickness (1.33 fold as compared with 1.22 fold at 20 Hz and 1.21 fold at 80 Hz) (p < 0.05). CONCLUSIONS: Our results indicate that NMES can preferentially stimulate contractions in deep abdominal stabilizing muscles. Most importantly, 50 Hz NMES produced greater muscle thickness increases than 20 or 80 Hz.

Clinical evaluation of transforaminal epidural steroid injection in patients with gadolinium enhancing spinal nerves associated with disc herniation.

BACKGROUND: Transforaminal epidural steroid injection (TFESI) of corticosteroid is frequently employed to mitigate the painful and disabling symptoms of lumbar disc herniation. However, the treatment outcome of TFESI in patients with radicular pain and inflamed neural structures as assessed by contrast-enhanced magnetic resonance imaging (MRI) has not been forthcoming. OBJECTIVES: To investigate functional improvement and pain reduction following TFESI in patients found to have nerve inflammation as evidenced by gadolinium-enhanced (MRI). STUDY DESIGN: Retrospective assessment. SETTING: Tertiary spinal intervention center, Daegu, Korea. METHODS: Thirty-seven patients were selected by strict inclusion criteria. Patients were classified into enhancing and non-enhancing groups as evidenced by gadolinium-enhanced MRI. The enhancing group was further divided into pre-dorsal roog ganglion (DRG) only enhanced group and pre-DRG and post-DRG enhanced group. Clinical outcomes were evidenced by numeric rating scale (NRS) and Oswestry disability index (ODI) at pretreatment, one week, and 4 weeks after treatment. RESULTS: The improvement of NRS and ODI in the enhanced group was greater than those of the non-enhanced group, at one week and 4 weeks after TFESI (P < 0.05). However there was no significant difference in improvement of NRS and ODI between pre-DRG only enhanced group and pre-DRG and post-DRG enhanced group at one week and 4 weeks after TFESI. LIMITATIONS: Retrospective chart review with a small sample size. CONCLUSION: The improvement of NRS and ODI in the enhanced group was significantly greater than those of the non-enhanced group after TFESI. Radicular pain and functional impairment in the presence of gadolinium enhancing spinal neural structures and lumbar disc herniation may be more responsive to TFESI than patients without enhancing neural structures.

Effect of hip abduction exercise with manual pelvic fixation on recruitment of deep trunk muscles.

OBJECTIVE: The aim of this study was to determine whether side-lying hip abduction exercise while applying manual pelvic fixation is more effective than hip abduction without manual pelvic fixation for promoting deep trunk muscle activity. DESIGN: This is a cross-sectional study comparing deep trunk muscle activation between hip abduction exercise without and with manual pelvic fixation in ten participants. Muscle activation was measured using fine-wire and surface electromyography. RESULTS: Hip abduction with manual pelvic fixation was found to result in significantly more recruitment of all studied deep trunk muscles except the ipsilateral obliquus externus compared with hip abduction without manual pelvic fixation (P < 0.05). The greatest increased activation was seen in the ipsilateral deep and superficial multifidus. The increase in deep multifidus percentage of maximal voluntary contraction was greater than that of the rectus abdominis, the obliquus externus, the transversuus abdominis/obliquus internus, the lumbar erector spinae, the superficial multifidus, and the gluteus medius (P < 0.05). The superficial multifidus percentage of maximal voluntary contraction was significantly increased over that of the rectus abdominis and the obliquus externus (P < 0.05). Moderate correlation between deep and superficial multifidus activation was found (Pearson correlation coefficient, 0.537). CONCLUSIONS: Hip abduction training in the side-lying position while applying manual pelvic fixation seems to be more effective for recruiting deep trunk muscles for dynamic lumbar spinal stabilization.

Changes in pain behavior and glial activation in the spinal dorsal horn after pulsed radiofrequency current administration to the dorsal root ganglion in a rat model of lumbar disc herniation: laboratory investigation.

OBJECT: Herniated discs can induce sciatica by mechanical compression and/or chemical irritation caused by proinflammatory cytokines. Using immunohistochemistry methods in the dorsal horn of a rat model of lumbar disc herniation, the authors investigated the effects of pulsed radiofrequency (PRF) current administration to the dorsal root ganglion (DRG) on pain-related behavior and activation of microglia, astrocytes, and mitogen-activated protein kinase. METHODS: A total of 33 Sprague-Dawley rats were randomly assigned to either a sham-operated group (n = 10) or a nucleus pulposus (NP)-exposed group (n = 23). Rats in the NP-exposed group were further subdivided into NP exposed with sham stimulation (NP+sham stimulation, n = 10), NP exposed with PRF (NP+PRF, n = 10), or euthanasia 10 days after NP exposure (n = 3). The DRGs in the NP+PRF rats were exposed to PRF waves (2 Hz) for 120 seconds at 45 V on postoperative Day 10. Rats were tested for mechanical allodynia 10 days after surgery and at 8 hours, 1 day, 3 days, 10 days, 20 days, and 40 days after PRF administration. Immunohistochemical staining of astrocytes (glial fibrillary acidic protein), microglia (OX-42), and phosphorylated extracellular signal-regulated kinases (pERKs) in the spinal dorsal horn was performed at 41 days after PRF administration. RESULTS: Starting at 8 hours after PRF administration, mechanical withdrawal thresholds dramatically increased; this response persisted for 40 days (p < 0.05). After PRF administration, immunohistochemical expressions of OX-42 and pERK in the spinal dorsal horn were quantitatively reduced (p < 0.05). CONCLUSIONS: Pulsed radiofrequency administration to the DRG reduced mechanical allodynia and downregulated microglia activity and pERK expression in the spinal dorsal horn of a rat model of lumbar disc herniation.

Motor outcome prediction using diffusion tensor tractography of the corticospinal tract in large middle cerebral artery territory infarct.

BACKGROUND: Middle cerebral artery (MCA) territory infarct is the most common type of cerebral vascular territory infarct. Accurate prediction of motor outcome is important for stroke rehabilitation. OBJECTIVES: We conducted an investigation of prognostic factors of motor outcome in patients with a large MCAterritory infarction, using diffusion tensor tractography (DTT) of the corticospinal tract (CST). METHODS: A total of 37 consecutive hemiparetic patients with a large MCA territory infarct were recruited for this study; DTT was performed within 5-30 days after onset. Patients were classified into three groups according to DTT findings: in group A - CST integrity was preserved around infarct regions, in group B - CSTs were discontinuous, and, in group C - the upper ends of CSTs did not reach infarcted regions. Fractional anisotropy (FA) ratio of the affected CST (versus the unaffected ipsilateral CST) was calculated, and evaluation of motor function was performed using the Motricity Index (MI), modified Brunnstrom classification (MBC) score, and the functional ambulation category (FAC) score at onset and at six months after onset. RESULTS: Significantly greater changes in motor function (MI, MBC, and FAC) were observed between onset and six months post-onset in group A, compared with groups B and C (p < 0.05). However, no significant difference was observed between groups B and C (p > 0.05). FA ratios showed positive correlation with six-month MIs, and scores for MBC and FAC (p < 0.05). CONCLUSIONS: Results of this study demonstrate the usefulness of early DTT findings of CSTs for prediction of motor outcome in patients with a large MCA territory infarct.

The effect of a hand-stretching device during the management of spasticity in chronic hemiparetic stroke patients.

OBJECTIVE: To describe a hand-stretching device that was developed for the management of hand spasticity in chronic hemiparetic stroke patients, and the effects of this device on hand spasticity. METHODS: Fifteen chronic hemiparetic stroke patients with finger flexor spasticity were recruited and randomly assigned to an intervention group (8 patients) or a control group (7 patients). The stretching device consists of a resting hand splint, a finger and thumb stretcher, and a frame. In use, the stretched state was maintained for 10 minutes per exercise session, and the exercise was performed twice daily for 4 weeks. Spasticity of finger flexor muscles in the two groups was assessed 3 times, 4 weeks apart, using the Modified Ashworth Scale (MAS). Patients in the intervention group were assessed twice (pre-1 and pre-2) before and once (post-1) after starting the stretching program. RESULTS: Mean MAS (mMAS) scores at initial evaluations were not significantly different at pre-1 in the intervention group and at 1st assessment in the control group (p>0.05). In addition, no significant differences were observed between mMAS scores at pre-1 and pre-2 in the intervention group (p>0.05). However, mMAS scores at post-1 were significantly lower than that at pre-2 in the intervention group (p<0.05). Within the control group, no significant changes in mMAS scores were observed between 1st, 2nd, and 3rd assessments (p>0.05). In addition, mMAS scores at post-1 in the intervention group were significantly decreased compared with those at the 3rd assessment in the control group (p<0.05). CONCLUSION: The devised stretching device was found to relieve hand spasticity effectively in chronic hemiparetic stroke patients.

Effects of abdominal hollowing during stair climbing on the activations of local trunk stabilizing muscles: a cross-sectional study.

OBJECTIVE: To examine using surface electromyography whether stair climbing with abdominal hollowing (AH) is better at facilitating local trunk muscle activity than stair climbing without AH. METHODS: Twenty healthy men with no history of low back pain participated in the study. Surface electrodes were attached to the multifidus (MF), lumbar erector spinae, thoracic erector spinae, transverse abdominus - internal oblique abdominals (TrA-IO), external oblique abdominals (EO), and the rectus abdominis. Amplitudes of electromyographic signals were measured during stair climbing. Study participants performed maximal voluntary contractions (MVC) for each muscle in various positions to normalize the surface electromyography data. RESULTS: AH during stair climbing resulted in significant increases in normalized MVCs in both MFs and TrA-IOs (p<0.05). Local trunk muscle/global trunk muscle ratios were higher during stair climbing with AH as compared with stair climbing without AH. Especially, right TrA-IO/EO and left TrA-IO/EO were significantly increased (p<0.05). CONCLUSION: Stair climbing with AH activates local trunk stabilizing muscles better than stair climbing without AH. The findings suggest that AH during stair climbing contributes to trunk muscle activation and trunk stabilization.