Achilles Tendinopathy, A Brief Review and Update of Current Literature.

ABSTRACT: Chronic pain in the Achilles tendon is a common problem in both athletes and nonathletes alike. The etiology for the development of Achilles tendinopathy has not been fully elucidated, and there remains multiple theories to explain the pain and dysfunction accompanying this condition. The diagnosis of Achilles tendon problems continues to rely on the clinical history and physical examination. The optimal management of pain, restoration of function, and return-to-sports participation with Achilles tendinopathy are evolving because of the advancement in technologies and research regarding its pathophysiology. This article aims to provide a brief review of the relevant anatomy, differential diagnosis, imaging findings, and an update of the literature on conservative and minimally invasive managements of chronic Achilles tendinopathy.

A randomized placebo-controlled trial of desipramine, cognitive behavioral therapy, and active placebo therapy for low back pain.

This clinical trial evaluated the independent and combined effects of a tricyclic antidepressant (desipramine) and cognitive behavioral therapy (CBT) for chronic back pain relative to an active placebo treatment. Participants (n = 142) were patients experiencing daily chronic back pain at an intensity of ≥4/10 who were randomized to a single-center, double-blind, 12-week, 4-arm, parallel groups controlled clinical trial of (1) low concentration desipramine titrated to reach a serum concentration level of 15 to 65 ng/mL; (2) CBT and active placebo medication (benztropine mesylate, 0.125 mg); (3) low concentration desipramine and CBT; and (4) active benztropine placebo medication. Participants completed the Differential Description Scale and Roland Morris Disability Questionnaires before and after treatment as validated measures of outcomes in back pain intensity and disability, respectively. Participants within each condition showed significant reductions from pre-treatment to post-treatment in pain intensity (mean changes ranged from = -2.58 to 3.87, Cohen's d's = 0.46-0.84) and improvements in pain disability (mean changes = -3.04 to 4.29, Cohen's d's = 0.54-0.88). However, intent-to-treat analyses at post-treatment showed no significant differences between any condition, with small effect sizes ranging from 0.06 to 0.27. The results from this clinical trial did not support the hypothesis that desipramine, CBT, or their combination would be statistically superior to an active medicine placebo for reducing chronic back pain intensity or disability. Key limitations included recruiting 71% of the planned sample size and use of multiple inclusion/exclusion criteria that may limit generalizability to broader populations of patients with chronic back pain.

Telehealth Therapy Effects of Nurses and Mental Health Professionals From 2 Randomized Controlled Trials for Chronic Back Pain.

OBJECTIVE: To compare the efficacy of mental health professional versus primary care nurse-delivered telehealth cognitive-behavioral therapy (CBT) and supportive care (SC) treatments for chronic low back pain, using data from 2 separate randomized controlled trials. Both trials were completed in the same hospital and used the same study design, research team, and outcome measures. MATERIALS AND METHODS: Participants from Study 1 (Mental Health Professional Study) (N=66; 2007 to 2011) and Study 2 (Nursing Study) (N=61; 2012 to 2016) were patients with chronic low back pain (≥4/10 intensity) randomized to either an 8-week CBT or an SC telehealth condition matched for contact frequency, format, and time. Participants completed validated measures of improvement in back pain disability (Roland Morris Disability Questionnaire [RMDQ]), pain intensity (Numeric Rating Scale [NRS]), depressive symptoms (Beck Depression Inventory 2 [BDI-2]), pain catastrophizing (Pain Catastrophizing Scale [PCS]), and overall improvement (Global Clinical Impressions [GCI]). RESULTS: Intent-to-treat analyses at posttreatment showed that scores on the RMDQ (Cohen d=0.33 to 0.55), NRS (d=0.45 to 0.90), PCS (d=0.21 to 0.41), and GCI (18.5% to 39.1%) improved significantly in both studies and in both treatments from pretreatment to posttreatment. Changes in BDI scores were inconsistent (d=-0.06 to 0.51). The analyses revealed no significant differences in treatment efficacy between the trained nurse versus the mental health professionals on the RMDQ, NRS, PCS, or GCI measures (P>0.20). DISCUSSION: Results from these clinical trials suggest that the benefits of home-based, telehealth-delivered CBT and SC treatments for chronic back pain were comparable when delivered by a primary care nurse or mental health professional.

Randomized Controlled Trial of Nurse-Delivered Cognitive-Behavioral Therapy Versus Supportive Psychotherapy Telehealth Interventions for Chronic Back Pain.

This study evaluated a nurse-delivered, telehealth intervention of cognitive-behavioral therapy (CBT) versus supportive psychotherapy for chronic back pain. Participants (N = 61) had chronic back pain (pain "daily" ≥6 months at an intensity of ≥4 of 10 scale) and were randomized to an 8-week, 12-session, CBT or to supportive care (SC) matched for frequency, format, and time, with each treatment delivered by a primary care nurse. The primary outcome was the Roland Morris Disability Questionnaire (RMDQ). Secondary outcomes included the numeric rating scale (NRS) and the Patient Global Impressions Scale (CGI). CBT participants (n = 30) showed significant improvements on the RMDQ (mean = 11.4 [SD = 5.9] vs 9.4 [SD = 6.1] at baseline and post-treatment, respectively, P < .05; d = .33), NRS (mean = 4.9 [SD = 2.1] vs 4.0 [SD = 1.9], respectively, P < .05; d = .45), and on the CGI (39.1% reporting "much improved" or "very much improved"). SC participants (n = 31) also showed significant improvements on the RMDQ (mean = 11.1 [SD = 5.4] vs 9.1 [SD = 5.2], respectively, P < .05; d = .38), the NRS, (mean = 5.0 [SD = 1.9] vs 3.8 [SD = 2.1], respectively, P < .05; d = .60), and 26.7% reporting "much improved" or "very much improved" on the CGI. Between groups comparisons of CBT and SC showed no differences on the study outcomes (Ps > .10). The results suggest that telehealth, nurse-delivered CBT, and SC treatments for chronic back pain can offer significant and relatively comparable benefits. PERSPECTIVE: This article describes the benefits of training primary care nurses to deliver evidence-based behavioral therapies for low back pain. Because of the high prevalence of chronic pain and the growing emphasis on nonopioid therapies, training nurses to provide behavior therapies could be a cost-effective way to improve pain management.

Randomized Controlled Trial of Telephone-delivered Cognitive Behavioral Therapy Versus Supportive Care for Chronic Back Pain.

OBJECTIVE: The objective of this study was to evaluate the efficacy of a telephone-delivered, home-based cognitive-behavioral intervention for chronic low back pain in comparison to a matched supportive care (SC) treatment. METHODS: Participants (N=66) were patients with chronic back pain that were randomized to either an 8-week Cognitive-Behavioral Therapy (CBT) or a SC condition matched for contact frequency, format, and time. Participants completed validated measures of improvement in back pain disability, pain severity, and overall improvement. RESULTS: Intent-to-treat analyses at posttreatment showed that the treatment groups not show significantly different improvements in back pain disability (mean changes, -2.4 and -2.6 for CBT and SC, respectively; Cohen d, 0.49 and 0.55, respectively) or reductions in pain severity (mean changes, -0.9 and -1.4 for CBT and SC respectively; Cohen d, 0.50, and 0.90, respectively). Participants rated their overall improvement levels at 31% (CBT) versus 18.5% (SC). DISCUSSION: Results from this clinical trial suggest that home-based, telephone-delivered CBT and SC treatments did not significantly differ in their benefits for back pain severity and disability, and may warrant further research for applications to hospital settings. Major limitations included recruitment difficulties that underpowered primary analyses, the lack of objective improvement measures, and the absence of a usual care/untreated control group for comparisons.

Time interval between concussions and symptom duration.

OBJECTIVE: To test the hypothesis that children with a previous history of concussion have a longer duration of symptoms after a repeat concussion than those without such a history. METHODS: Prospective cohort study of consecutive patients 11 to 22 years old presenting to the emergency department of a children's hospital with an acute concussion. The main outcome measure was time to symptom resolution, assessed by the Rivermead Post-Concussion Symptoms Questionnaire (RPSQ). Patients and providers completed a questionnaire describing mechanism of injury, associated symptoms, past medical history, examination findings, diagnostic studies, and the RPSQ. Patients were then serially administered the RPSQ for 3 months after the concussion or until all symptoms resolved. RESULTS: A total of 280 patients were enrolled over 12 months. Patients with a history of previous concussion had a longer duration of symptoms than those without previous concussion (24 vs 12 days, P = .02). Median symptom duration was even longer for patients with multiple previous concussions (28 days, P = .03) and for those who had sustained a concussion within the previous year (35 days, P = .007) compared with patients without those risk factors. In a multivariate model, previous concussion, absence of loss of consciousness, age ≥13, and initial RPSQ score >18 were significant predictors of prolonged recovery. CONCLUSIONS: Children with a history of a previous concussion, particularly recent or multiple concussions, are at increased risk for prolonged symptoms after concussion. These findings have direct implications on the management of patients with concussion who are at high risk for repeat injuries.

40-Hz square-wave stimulation requires less energy to produce muscle contraction: compared with the TASER® X26 conducted energy weapon.

Conducted energy weapons (CEWs) (including the Advanced TASER(®) X26 model produced by TASER International, Inc.) incapacitate individuals by causing muscle contractions. In this study using anesthetized swine, the potential incapacitating effect of primarily monophasic, 19-Hz voltage imposed by the commercial CEW was compared with the effect of voltages imposed by a laboratory device that created 40-Hz square waves. Forces of muscle contraction were measured with the use of strain gauges. Stimulation with 40-Hz square waves required less pulse energy than stimulation with the commercial CEW to produce similar muscle contraction. The square-pulse stimulation, at the higher repetition rate, caused a more complete tetanus at a lower energy. Use of such a simple shape of waveform may be used to make future nonlethal weapon devices more efficient.

An automatic MEG low-frequency source imaging approach for detecting injuries in mild and moderate TBI patients with blast and non-blast causes.

Traumatic brain injury (TBI) is a leading cause of sustained impairment in military and civilian populations. However, mild (and some moderate) TBI can be difficult to diagnose because the injuries are often not detectable on conventional MRI or CT. Injured brain tissues in TBI patients generate abnormal low-frequency magnetic activity (ALFMA, peaked at 1-4 Hz) that can be measured and localized by magnetoencephalography (MEG). We developed a new automated MEG low-frequency source imaging method and applied this method in 45 mild TBI (23 from combat-related blasts, and 22 from non-blast causes) and 10 moderate TBI patients (non-blast causes). Seventeen of the patients with mild TBI from blasts had tertiary injuries resulting from the blast. The results show our method detected abnormalities at the rates of 87% for the mild TBI group (blast-induced plus non-blast causes) and 100% for the moderate group. Among the mild TBI patients, the rates of abnormalities were 96% and 77% for the blast and non-blast TBI groups, respectively. The spatial characteristics of abnormal slow-wave generation measured by Z scores in the mild blast TBI group significantly correlated with those in non-blast mild TBI group. Among 96 cortical regions, the likelihood of abnormal slow-wave generation was less in the mild TBI patients with blast than in the mild non-blast TBI patients, suggesting possible protective effects due to the military helmet and armor. Finally, the number of cortical regions that generated abnormal slow-waves correlated significantly with the total post-concussive symptom scores in TBI patients. This study provides a foundation for using MEG low-frequency source imaging to support the clinical diagnosis of TBI.

Muscle contraction during electro-muscular incapacitation: A comparison between square-wave pulses and the TASER(®) X26 Electronic control device.

Electronic control devices (including the Advanced TASER(®) X26 model produced by TASER International) incapacitate individuals by causing muscle contractions. To provide information relevant to development of future potential devices, effects of monophasic square waves with different parameters were compared with those of the X26 electronic control device, using two animal models (frogs and swine). Pulse power, electrical pulse charge, pulse duration, and pulse repetition frequency affected muscle contraction. There was no difference in the charge required, between the square waveform and the X26 waveform, to cause approximately the same muscle-contraction response (in terms of the strength-duration curve). Thus, on the basis of these initial studies, the detailed shape of a waveform may not be important in terms of generating electro-muscular incapacitation. More detailed studies, however, may be required to thoroughly test all potential waveforms to be considered for future use in ECDs.

Absence of corneal endothelium injury in non-human primates treated with and without ophthalmologic drugs and exposed to 2.8 GHz pulsed microwaves.

Microwave-induced corneal endothelial damage was reported to have a low threshold (2.6 W/kg), and vasoactive ophthalmologic medications lowered the threshold by a factor of 10-0.26 W/kg. In an attempt to confirm these observations, four adult male Rhesus monkeys (Macaca mulatta) under propofol anesthesia were exposed to pulsed microwaves in the far field of a 2.8 GHz signal (1.43 +/- 0.06 micros pulse width, 34 Hz pulse repetition frequency, 13.0 mW/cm(2) spatial and temporal average, and 464 W/cm(2) spatial and temporal peak (291 W/cm(2) square wave equivalent) power densities). Corneal-specific absorption rate was 5.07 W/kg (0.39 W/kg/mW/cm(2)). The exposure resulted in a 1.0-1.2 degrees C increase in eyelid temperature. In Experiment I, exposures were 4 h/day, 3 days/week for 3 weeks (nine exposures and 36 h total). In Experiment II, these subjects were pretreated with 0.5% Timolol maleate and 0.005% Xalatan(R) followed by 3 or 7 4-h pulsed microwave exposures. Under ketamine-xylazine anesthesia, a non-contact specular microscope was used to obtain corneal endothelium images, corneal endothelial cell density, and pachymetry at the center and four peripheral areas of the cornea. Ophthalmologic measurements were done before and 7, 30, 90, and 180 days after exposures. Pulsed microwave exposure did not cause alterations in corneal endothelial cell density and corneal thickness with or without ophthalmologic drugs. Therefore, previously reported changes in the cornea exposed to pulsed microwaves were not confirmed at exposure levels that are more than an order of magnitude higher.

Integrated imaging approach with MEG and DTI to detect mild traumatic brain injury in military and civilian patients.

Traumatic brain injury (TBI) is a leading cause of sustained impairment in military and civilian populations. However, mild (and some moderate) TBI can be difficult to diagnose due to lack of obvious external injuries and because the injuries are often not visible on conventional acute MRI or CT. Injured brain tissues in TBI patients generate pathological low-frequency neuronal magnetic signal (delta waves 1-4 Hz) that can be measured and localized by magnetoencephalography (MEG). We hypothesize that abnormal MEG delta waves originate from gray matter neurons that experience de-afferentation due to axonal injury to the underlying white matter fiber tracts, which is manifested on diffusion tensor imaging (DTI) as reduced fractional anisotropy. The present study used a neuroimaging approach integrating findings of magnetoencephalography (MEG) and diffusion tensor imaging (DTI), evaluating their utility in diagnosing mild TBI in 10 subjects in whom conventional CT and MRI showed no visible lesions in 9. The results show: (1) the integrated approach with MEG and DTI is more sensitive than conventional CT and MRI in detecting subtle neuronal injury in mild TBI; (2) MEG slow waves in mild TBI patients originate from cortical gray matter areas that experience de-afferentation due to axonal injuries in the white matter fibers with reduced fractional anisotropy; (3) findings from the integrated imaging approach are consistent with post-concussive symptoms; (4) in some cases, abnormal MEG delta waves were observed in subjects without obvious DTI abnormality, indicating that MEG may be more sensitive than DTI in diagnosing mild TBI.

Electromuscular incapacitation results from stimulation of spinal reflexes.

Electronic stun devices (ESD) often used in law enforcement, military action or self defense can induce total body uncoordinated muscular activity, also known as electromuscular incapacitation (EMI). During EMI the subject is unable to perform purposeful or coordinated movements. The mechanism of EMI induction has not been reported, but has been generally thought to be direct muscle and nerve excitation from the fields generated by ESDs. To determine the neuromuscular mechanisms linking ESD to induction of EMI, we investigated EMI responses using an anesthetized pig model. We found that EMI responses to ESD application can best be simulated by simultaneous stimulation of motor and sensory peripheral nerves. We also found that application of local anesthetics limited the response of ESD to local muscle stimulation and abolished the total body EMI response. Stimulation of the pure sensory peripheral nerves or nerves that are primarily motor nerves induced muscle responses that are consistent with well defined spinal reflexes. These findings suggest that the mechanism of ESD-induced EMI is mediated by excitation of multiple simultaneous spinal reflexes. Although direct motor-neuron stimulation in the region of ESD contact may significantly add to motor reactions from ESD stimulation, multiple spinal reflexes appear to be a major, and probably the dominant mechanism in observed motor response.

Radio frequency electromagnetic fields: mild hyperthermia and safety standards.

This chapter is a short review of literature that serves as the basis for current safe exposure recommendations by ICNIRP (International Commission on Non-Ionizing Radiation Protection, 1998). and the IEEE C95.1 (IEEE Standard for Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz, 2005) for exposure to radio frequency electromagnetic radiation (RF-EMF). Covered here are topics on dosimetry, thermoregulatory responses, behavioral responses, and how these have been used to derive safe exposure limits for humans to RF-EMF. Energy in this portion of the electromagnetic spectrum, 3 kHz-300 GHz, can be uniquely absorbed and is different from ionizing radiation both in dosimetry and effects. The deposition of thermalizing energy deep in the body by exposure to RF-EMF fields provides a unique exception to the energy flows normally encountered by humans. Behavioral effects of RF-EMF exposure range from detection to complete cessation of trained behaviors. RF-EMF is detectable and can in most cases, presumably by thermal mechanisms, support aversion and disruption or complete cessation (work stoppage) of behavior. Safety standards are based on behavioral responses by laboratory animals to RF-EMF, enhanced by careful studies of human thermoregulatory responses at four specific RF frequencies, thereby providing a conservative level of protection from RF-EMF for humans.

Behavioral and cognitive effects of microwave exposure.

This paper presents an overview of the recent behavioral literature concerning microwave exposure and discusses behavioral effects that have supported past exposure standards. Other effects, which are based on lower levels of exposure, are discussed as well, relative to setting exposure standards. The paper begins with a brief discussion of the ways in which behavioral end points are investigated in the laboratory, together with some of the methodological considerations pertinent to such studies when radio frequency (RF) exposure is involved. It has been pointed out by several sources that exposure to RF radiation can lead to changes in the behavior of humans and laboratory animals that can range from the perceptions of warmth and sound to lethal body temperatures. Behavior of laboratory animals can be perturbed and, under certain other conditions, animals will escape and subsequently avoid RF fields; but they will also work to obtain a burst of RF energy when they are cold. Reports of change of cognitive function (memory and learning) in humans and laboratory animals are in the scientific literature. Mostly, these are thermally mediated effects, but other low level effects are not so easily explained by thermal mechanisms. The phenomenon of behavioral disruption by microwave exposure, an operationally defined rate decrease (or rate increase), has served as the basis for human exposure guidelines since the early 1980s and still appears to be a very sensitive RF bioeffect. Nearly all evidence relates this phenomenon to the generation of heat in the tissues and reinforces the conclusion that behavioral changes observed in RF exposed animals are thermally mediated. Such behavioral alteration has been demonstrated in a variety of animal species and under several different conditions of RF exposure. Thermally based effects can clearly be hazardous to the organism and continue to be the best predictor of hazard for homosapiens. Nevertheless, similar research with man has not been conducted. Although some studies on human perception of RF exist, these should be expanded to include a variety of RF parameters.

Microwave effects on the nervous system.

Studies have evaluated the electroencephalography (EEG) of humans and laboratory animals during and after Radiofrequency (RF) exposures. Effects of RF exposure on the blood-brain barrier (BBB) have been generally accepted for exposures that are thermalizing. Low level exposures that report alterations of the BBB remain controversial. Exposure to high levels of RF energy can damage the structure and function of the nervous system. Much research has focused on the neurochemistry of the brain and the reported effects of RF exposure. Research with isolated brain tissue has provided new results that do not seem to rely on thermal mechanisms. Studies of individuals who are reported to be sensitive to electric and magnetic fields are discussed. In this review of the literature, it is difficult to draw conclusions concerning hazards to human health. The many exposure parameters such as frequency, orientation, modulation, power density, and duration of exposure make direct comparison of many experiments difficult. At high exposure power densities, thermal effects are prevalent and can lead to adverse consequences. At lower levels of exposure biological effects may still occur but thermal mechanisms are not ruled out. It is concluded that the diverse methods and experimental designs as well as lack of replication of many seemingly important studies prevents formation of definite conclusions concerning hazardous nervous system health effects from RF exposure. The only firm conclusion that may be drawn is the potential for hazardous thermal consequences of high power RF exposure.

Thermal modeling of millimeter wave damage to the primate cornea at 35 GHz and 94 GHz.

Recent data on damage to the primate cornea from exposure to millimeter wave radiation are interpreted in terms of a simple thermal model. The measured temperature increases during the exposures (duration 1-5 s, 35 or 94 GHz, 2-7 W cm(-2)) agree with the model within the variability of the data. The thresholds for damage to the cornea (staining of the corneal epithelium by fluorescein and corneal edema) correspond to temperature increases of about 20 degrees C at both irradiation frequencies. Within the limits of the one-dimensional model, thresholds for thermal damage to the cornea can be predicted for a range of exposure conditions.

Millimeter wave absorption in the nonhuman primate eye at 35 GHz and 94 GHz.

The purpose of this study was to evaluate anterior segment bioeffects of pulsed 35 GHz and 94 GHz microwave exposure in the nonhuman primate eye. Five juvenile rhesus monkeys (Macaca mulatta) underwent baseline anterior segment ocular assessment consisting of slit lamp examination, corneal topography, specular microscopy, and pachymetry. These studies were repeated after exposure of one eye to pulsed 35 GHz or 94 GHz microwaves at varied fluences, with the other eye serving as a control. The mean fluence required to produce a threshold corneal lesion (faint epithelial edema and fluorescein staining) was 7.5 J cm(-2) at 35 GHz and 5 J cm(-2) at 94 GHz. Transient changes in corneal topography and pachymetry were noted at these fluences. Endothelial cell counts remained unchanged. Threshold corneal injury from 35 GHz and 94 GHz microwave exposure is produced at fluences below those previously reported for CO2 laser radiation. These data may help elucidate the mechanism of thermal injury to the cornea, and resolve discrepancies between IEEE C95.1 (1999), NCRP (1986), and ICNIRP (1998) safety standards for exposure to non-ionizing radiation at millimeter wavelengths.