F. Richard Clemente

Contralateral High or a Combination of High- and Low-Frequency Transcutaneous Electrical Nerve Stimulation Reduces Mechanical Allodynia and Alters Dorsal Horn Neurotransmitter Content in Neuropathic Rats

UNLABELLEDnThe purpose of the study was to examine the effect of 3 different application strategies for transcutaneous electrical nerve stimulation (TENS) on neuropathy-induced allodynia and dorsal horn neurotransmitter content. Rats were treated with high-frequency, low-frequency, or a combination of high and low-frequency stimulation. TENS was delivered through self-adhesive electrodes daily for 1 hour to rats with a right-sided chronic constriction injury (CCI). Stimulation was delivered to skin or acupuncture points on the left and mechanical and thermal pain thresholds were assessed in the right hind paw. Neurotransmitter content was assessed bilaterally in the dorsal horn of the spinal cord. Daily, high-frequency or a combination of high- and low-frequency TENS reduced mechanical (P < .001), but not thermal allodynia in the right hind paw when compared with untreated CCI rats. Daily high frequency TENS elevated the dorsal horn synaptosomal content of GABA bilaterally (P < .014) and a combination of high- and low-frequency TENS elevated the dorsal horn content of aspartate (P < .001), glutamate (P < .001) and glycine (P < .001) bilaterally over that seen in untreated CCI rats. The present findings support a contralateral approach to the application of TENS and suggest that distinct strategies for TENS application may differentially alter neurotransmission in the central nervous system.nnnPERSPECTIVEnBecause CCI rats are reminiscent of humans with neuropathy, daily high or a combination of high- and low-frequency TENS may reduce mechanical allodynia in humans with neuropathic pain. Because the 2 intervention strategies produce distinctive alterations in spinal cord neurotransmitter content, each may represent a distinctive option for treatment.

High-frequency transcutaneous electrical nerve stimulation alters thermal but not mechanical allodynia following chronic constriction injury of the rat sciatic nerve☆☆☆★

OBJECTIVEnTo determine if daily transcutaneous electrical nerve stimulation (TENS) can alter the thermal and mechanical allodynia that develops after chronic constriction injury (CCI) to the right sciatic nerve of rats.nnnDESIGNnA completely randomized experimental design was used. Four groups of rats underwent CCI surgery to the right sciatic nerve and either were not treated with TENS or received TENS starting at different times after the CCI surgery.nnnINTERVENTIONSnTENS was delivered daily for 1 hour to CCI rats through self-adhesive electrodes applied to skin innervated by the right dorsal rami of lumbar spinal nerves L1-6. Rats of different groups received daily TENS starting immediately, 20 to 30 hours, or 3 days after the CCI surgery.nnnMAIN OUTCOME MEASUREnThermal and mechanical pain thresholds of hind paws were assessed bilaterally in all rats twice before the CCI surgery (baseline) and then 2, 7, 12, and 14 days after surgery. Thermal and mechanical allodynia were expressed as difference scores between the pain thresholds of right and left hind paws. These values were normalized to differences that existed between the two paws at baseline.nnnRESULTSnDaily TENS beginning immediately after CCI surgery prevented the development of thermal allodynia at all assessment times (p < .05). Daily TENS starting 1 day after surgery reduced thermal allodynia, but only on days 2 and 14 (p < .05). Daily TENS beginning 3 days after surgery had no effect on the development of thermal allodynia. Regardless of when it was started, daily TENS did not consistently alter mechanical allodynia in CCI rats.nnnCONCLUSIONnIt appears that daily TENS can prevent thermal but not mechanical allodynia in this model. However, early intervention with the treatment is critical if it is to be effective at all.

Variation in the triceps brachii muscle: A fourth muscular head

Routine cadaver dissection has resulted in the identification of a fourth head of the triceps brachii muscle on the left side in one specimen. This novel arrangement demonstrated a single tendon arising from the proximal posteromedial aspect of the humeral shaft, distal to the shoulder capsule. The tendon of this fourth head passed along the medial aspect of the humerus and gave way to a muscle belly on the medial surface of the distal one‐third of the humerus. The tendon of the fourth head passed directly over the neurovascular bundle containing the radial nerve and deep brachial artery at approximately the point where the neurovascular bundle entered the radial sulcus. This close positional relationship between the tendon of the fourth head, the radial nerve, and the deep brachial artery has prompted us to speculate on the possible clinical significance of this finding in relation to radial nerve palsy and arterial compression. Additionally, the position of the muscle belly, lying in close proximity to the ulnar groove, invites speculation on the role of the fourth head in cases of snapping elbow. To the authors knowledge, a description of the muscular fourth head of the triceps as seen in the present work has not been noted in previous literature. Clin. Anat. 10:259–263, 1997.

The relationship between dorsal horn neurotransmitter content and allodynia in neuropathic rats treated with high-frequency transcutaneous electric nerve stimulation

OBJECTIVEnTo examine the relation between axon terminal neurotransmitter content in the dorsal horn and allodynia in neuropathic rats treated with high-frequency transcutaneous electric nerve stimulation (TENS).nnnDESIGNnA completely randomized experimental design. Two groups of rats received a chronic constriction injury to the right sciatic nerve, and 2 groups did not. The rats were either treated or not treated with TENS.nnnSETTINGnResearch laboratory.nnnANIMALSnAdult male Sprague-Dawley rats (150-165g).nnnINTERVENTIONSnTENS was delivered daily for 1 hour to the chronic constriction injury rats or to the uninjured rats through self-adhesive electrodes applied to the skin innervated by the right dorsal rami of lumbar spinal nerves 1 to 6.nnnMAIN OUTCOME MEASURESnThermal and mechanical pain thresholds were assessed bilaterally in the hind paws of all rats twice before the chronic constriction injury surgery (baseline) and then 12 days after the surgery. An analogous time frame of assessment was used for rats that did not have chronic constriction injury surgery. Thermal and mechanical allodynia were expressed as difference scores between the pain thresholds of the right and left hind paws. These values were normalized to differences that existed between the 2 paws at baseline. The amino acid content of dorsal horn axon terminals was assessed bilaterally with high-pressure liquid chromatography, and values were normalized to wet weight.nnnRESULTSnThe mean level of thermal and mechanical allodynia did not differ between the TENS-treated and untreated rats with chronic constriction injury. However, there was a significant relation between the dorsal horn, axon terminal content of glutamate (adjusted R(2)=.45, P<.01) and glycine (adjusted R(2)=.51, P<.005) and the magnitude of mechanical allodynia present in TENS-treated chronic constriction injury rats, but not in any other group. As axon terminal glutamate and glycine decreased in the right dorsal horn and increased in the left, mechanical allodynia was reduced or absent. When this trend was reversed, mechanical allodynia was more severe. Daily TENS also reduced the mean axon terminal content of aspartate, glutamate, and glycine bilaterally in the chronic constriction injury rats from the level observed in untreated neuropathic rats (P<.05).nnnCONCLUSIONnThe variability in responsiveness of mechanical allodynia to daily TENS treatment in neuropathic rats is related to the axon terminal content of glutamate and glycine in the dorsal horn. These findings may help explain a similar variability in humans when TENS is used to treat neuropathic pain.

A variation in the organization of abductor pollicis longus

The abductor pollicis longus (APL) muscle has been studied bilaterally in 50 cadavers. A variation in the organization of the muscle was found bilaterally in 15 of the 50 specimens. The novel muscular arrangement gives the appearance of being an additional muscle belly arising from the lateral aspect of the distal portion of the typical abductor pollicis longus muscle belly. This variation in the arrangement also creates a retinacular‐like tunnel which encases the tendons of the extensor carpi radialis longus and the extensor carpi radialis brevis muscles. To the authors knowledge, this arrangement has not been cited in the recent medical literature. An understanding of this unusual finding may be clinically relevant in describing the dorso‐lateral compartment of the distal forearm.

Transcutaneous neuromuscular electrical stimulation effect on the degree of microvascular perfusion in autonomically denervated rat skeletal muscle

OBJECTIVEnTo determine the effect of transcutaneous neuromuscular electrical stimulation (TNMES) on the degree of microvascular perfusion in autonomically denervated skeletal muscle.nnnDESIGNnA completely randomized experimental design was used to compare the effects of TNMES on the degree of microvascular perfusion in the tibialis anterior (TA) and extensor digitorum longus (EDL) muscles from autonomically denervated rats (Ch-TES) to the degree of microvascular perfusion in the same muscles of untreated controls, rats receiving only TNMES (TES), and rats receiving only autonomic denervation (shams).nnnINTERVENTIONnAll electrical stimulation treatments were delivered via carbon silicone surface electrodes, and evoked sustained tetanic contraction of the TA and EDL muscles. Autonomic denervation was achieved by the application of chlorisondamine.nnnMAIN OUTCOME MEASURESnThe degree of microvascular perfusion was determined for the deep (DTA) and superficial (STA) region of the TA muscle and the EDL muscle by calculating their perfused microvessel/muscle fiber (PV/F) ratio.nnnRESULTSnThe PV/F ratio in the DTA from Ch-TES animals was greater (p < or = .05) than that in the same muscle from control and sham animals. The PV/F ratios in the STA and EDL from Ch-TES animals were not significantly (p > .05) different from the PV/F ratio in the respective muscles of shams.nnnCONCLUSIONSnThe response of the microvasculature in autonomically denervated skeletal muscle to TNMES that evokes muscle contraction is variable, and (2) mechanisms other than autonomic regulation may be involved in this hyperemic response.

The effect of Astym® Therapy on muscle strength: a blinded, randomized, clinically controlled trial

BackgroundAstym® therapy is a manual therapy intervention used to stimulate tissue healing, decrease pain, improve mobility, and improve muscle performance associated with musculoskeletal pathology. The purpose of this study was to determine if Astym therapy administered to the lower extremity would result in an immediate change of maximal force output during a unilateral isometric squat test among individuals with a lower extremity injury.MethodsForty-five subjects (14 males; 31females) between 18 and 65 years of age were randomized into 3 treatment groups: 1) Control group – received no treatment 2) Placebo group – received a sham Astym treatment 3) Astym therapy group– received Astym therapy to the lower extremity. A baseline measure of maximal force output (pre-test) during a unilateral isometric squat was performed. The subjects then received the designated treatment intervention. Immediately following the treatment intervention, maximal force output (post-test) was retested using identical testing procedures by an investigator who was blinded to the treatment intervention received by the subjects. The percent change of maximal force output from pre-test to post-test measures was compared using a one-way analysis of variance. A Tukey’s post-hoc analysis determined the statistical differences between the groups.ResultsThe treatment intervention had a significant effect on the percent change of maximal force output [F(2,42)u2009=u20097.91, pu2009=u20090.001]. Tukey’s post hoc analysis demonstrated that the percent change of maximal force output was significantly greater in the Astym group (15u2009±u200918xa0% change of Newtons) compared to the placebo (−6u2009±u200911xa0% change of Newtons; pu2009=u20090.0001) and control (−1u2009±u200917xa0% change of Newtons; pu2009=u20090.0014) groups. No significant difference (pu2009=u20090.68) was noted between the control and placebo groups.ConclusionsAstym therapy to the involved lower extremity increased maximum force output during an isometric squat test immediately following treatment. The results of this study suggest that Astym therapy can immediately improve muscle performance (maximal force output) for patients presenting with muscular weakness caused by a lower extremity musculoskeletal injury.Trial registrationClinicaltrials.gov NCT02349230. Registered 23 January 2015.

A novel approach to the dissection of the human knee

The knee is one of the most frequently injured joints of the human body with injuries affecting the general population and the athletic population of many age groups. Dissection procedures for the knee joint typically do not allow unobstructed visualization of the anterior cruciate or posterior cruciate ligaments without sacrificing the collateral ligaments. In many cases, the relationships of the intraarticular structures are lost as dissection systematically removes superficial structures to gain access to deeper structures. The authors present an alternative technique for dissection of the human knee joint that allows maximal visualization of intraarticular structures such as the cruciate ligaments and menisci with minimal disturbance to the tibial and fibular collateral ligaments, thus preserving the relationships of the ligamentous and intraarticular structures. Anat Sci Ed 2:41–46, 2009.

Approach to dissection of the anterior thoracic wall and the entrance to the thoracic cavity

Dissection of the anterior chest wall typically precedes the opening of the thoracic cavity. The techniques for exposing and subsequently reflecting or removing the structures of the anterior chest wall have been well described. However, these approaches that involve the systematic dissection of the layers of tissue overlying the anterior thoracic wall prior to the removal of the anterior thoracic wall render the pectoral regions and axillas unfit for continued study. The authors offer an alternative dissection that allows continued access to the thoracic cavity while maintaining the integrity of the pectoral and axillary regions. This new technique may facilitate more efficient use and complete study of each specimen. Clin. Anat. 11:246–249, 1998.