Local cooling restores microcirculatory hemodynamics after closed soft-tissue trauma in rats

Devices for osteoarthritis symptoms treatment: a patent review

INTRODUCTION

Osteoarthritis is a musculoskeletal disease that can lead to the loss and inability of those affected to perform normal daily functions, which leads to a decrease in quality of life. The main symptoms of osteoarthritis are tenderness, joint pain, stiffness, crepitus, limited movement, and local inflammation.

AREAS COVERED

The selected patents were deposited from 2010 to April 2022 involving 57 documents that were in line with the study objective in the final selection. The patents were classified in years, country, and applicants. Also, the therapeutic fields that presented the most documents were electrical stimulation, phototherapy, and ultrasound, followed by magnetic, electromagnetic, and thermotherapy. Therefore, the most current therapies used in the documents are already on the market.

EXPERT OPINION

Although the OA is cureless, non-surgical treatments are classified as the primary management approach for this disease. The pharmacological and non-pharmacological therapies are employed to reduce its prevalence and ensure the effectiveness of treatments. A strategy for relieving OA symptoms is non-pharmacological treatment, which can be based on exercise and patient education, combined with other alternative therapies. These therapies are used as supplements to the main OA treatments, enhancing the effectiveness of treatment outcomes.

A three-dimensional model of transient bioheat transfer in the lower extremity during cryotherapy

The purpose of this research was to create a computational model of the human thigh undergoing cryotherapy. The tissue temperatures were measured for five cold pack temperatures of -8°C, -4°C, 0°C, 4°C, and 8°C in addition to six different time intervals of cold application and ice removal. The depth of cold penetration and duration of local tissue cooling were investigated at 10 points during 30 min of application and 7 h of post-application. The model was created in CATIA, using a mid-axial cut of the human thigh MRI without pathology. After validation by the available clinical data, this research applied the finite-volume discretization method to solve bioheat transfer equations. A 16°C decrease in the cold pack temperature reduced the tissue temperatures located 1 and 2 cm below the fat by almost 3.34°C and 1.4°C, respectively, after 30 min of cold application. It took the tissues 10-15 min to start cooling down, and the temperature reached its plateau after 100 min. Thirty minutes of cold application declined the superficial tissue and deep tissue temperatures near the bone by 22.59°C and 0.48°C, respectively. Intense cryotherapy led to an insignificant change in the deep tissue temperature at 2 cm and deeper below the fat tissue. After ice removal, tissues continued cooling down for about 8 min until 40 min, depending on the tissue depth. This study proposed a 100-min cold therapy with 10 min of ice removal to optimize tissue cooling.

Effects of Systemic Hypothermia on Microcirculation in Conditions of Hemodynamic Stability and in Hemorrhagic Shock

INTRODUCTION

Although hypothermia is independently associated with an increased mortality in trauma patients, it might be an effective therapeutic approach for otherwise lethal hemorrhage. The effect of hypothermia on microcirculation, however, has been poorly studied in this setting. Our goal was to characterize the effects of hypothermia on microcirculation in normal conditions and in severe hemorrhagic shock.

METHODS

In anesthetized and mechanically ventilated sheep, we measured cardiac output (CO), renal blood flow (RBF), and systemic and renal O2 consumption (VO2). Cortical renal, intestinal villi, and sublingual microcirculation was assessed by IDF-videomicroscopy. After basal measurements, sheep were assigned to hypothermia (n = 12) and normothermia (n = 12) groups. Central temperature was reduced to ∼34°C and maintained at baseline in each group, respectively. Measurements were repeated after 1 h of hemodynamic stable conditions and 1 h of severe hemorrhagic shock.

RESULTS

In conditions of hemodynamic stability, the hypothermia group showed lower CO, RBF, and systemic and renal VO2 than the normothermia group. Red blood cell velocity was also lower in renal, villi, and sublingual microvascular beds (836 ± 195 vs. 1,066 ± 162, 916 ± 105 vs. 1051 ± 41, and 970 ± 182 vs. 1,102 ± 49 μm/s, respectively; P < 0.0001 for all). In hemorrhagic shock, most of the microvascular variables were similarly compromised in both the groups. In hypo- and normothermia groups, the percentage of reduction in perfused vascular density was higher in renal than in intestinal and sublingual microcirculation (66 ± 31 vs. 31 ± 23 and 15 ± 15%, and 78 ± 26 vs. 32 ± 37 and 18 ± 21%, P < 0.01 for both).

CONCLUSIONS

This is the first experimental study assessing the effect of systemic hypothermia on microcirculation in severe hemorrhagic shock. The main finding was that hypothermia did not hamper additionally the microcirculatory derangements induced by hemorrhagic shock. In addition, renal microcirculation was more susceptible to hemorrhagic shock than villi and sublingual microcirculation.

The cold truth: the role of cryotherapy in the treatment of injury and recovery from exercise

Cryotherapy is utilized as a physical intervention in the treatment of injury and exercise recovery. Traditionally, ice is used in the treatment of musculoskeletal injury while cold water immersion or whole-body cryotherapy is used for recovery from exercise. In humans, the primary benefit of traditional cryotherapy is reduced pain following injury or soreness following exercise. Cryotherapy-induced reductions in metabolism, inflammation, and tissue damage have been demonstrated in animal models of muscle injury; however, comparable evidence in humans is lacking. This absence is likely due to the inadequate duration of application of traditional cryotherapy modalities. Traditional cryotherapy application must be repeated to overcome this limitation. Recently, the novel application of cooling with 15 °C phase change material (PCM), has been administered for 3-6 h with success following exercise. Although evidence suggests that chronic use of cryotherapy during resistance training blunts the anabolic training effect, recovery using PCM does not compromise acute adaptation. Therefore, following exercise, cryotherapy is indicated when rapid recovery is required between exercise bouts, as opposed to after routine training. Ultimately, the effectiveness of cryotherapy as a recovery modality is dependent upon its ability to maintain a reduction in muscle temperature and on the timing of treatment with respect to when the injury occurred, or the exercise ceased. Therefore, to limit the proliferation of secondary tissue damage that occurs in the hours after an injury or a strenuous exercise bout, it is imperative that cryotherapy be applied in abundance within the first few hours of structural damage.

Effects of cryotherapy on the regeneration process and muscular mechanical properties after lacerative injury model

Cryotherapy is a therapeutic modality widely used for the treatment of muscle injuries to control pain and inflammatory processes. This study aimed to investigate the effects of cryotherapy on the inflammatory and oxidative stress parameters and mechanical properties of, and pain in, the skeletal muscles of rats with lacerative muscle injury. The rats were anesthetized with 4% isoflurane and subjected to gastrocnemius muscle laceration injury. After injury, all animals in the intervention groups received cryotherapy treatment for 20 minutes using plastic bags containing crushed ice. The protocol comprised three daily applications at 3-hour intervals on the day of injury, with reapplication 24 hours later. Seventy-two male Wistar rats were divided into three groups: sham, muscle injury (MI), and MI + cryotherapy (MI + cryo). Muscle mechanical properties were analyzed by mechanical tensile testing on day 7 after injury. The MI + cryo group showed reduced TNF-α, IFN-γ, and IL1β levels; elevated IL4, IL6, and IL10 levels; reduced oxidant production and carbonyl levels; and elevated sulfhydryl contents. Animals that underwent tissue cooling showed superoxide dismutase activity and glutathione levels close to those of the animals in the sham group. The MI and MI + cryo groups showed reduced values of the evaluated mechanical properties and lower mechanical thresholds compared to those of the animals from the sham group. Our results demonstrated that the proposed cryotherapy protocol reduced the inflammatory process and controlled oxidative stress but did not reverse the changes in the mechanical properties of muscle tissues or provide analgesic effects within the time frame analyzed.

Don't Lose Your Cool With Cryotherapy: The Application of Phase Change Material for Prolonged Cooling in Athletic Recovery and Beyond

Strenuous exercise can result in muscle damage in both recreational and elite athletes, and is accompanied by strength loss, and increases in soreness, oxidative stress, and inflammation. If the aforementioned signs and symptoms associated with exercise-induced muscle damage are excessive or unabated, the recovery process becomes prolonged and can result in performance decrements; consequently, there has been a great deal of research focussing on accelerating recovery following exercise. A popular recovery modality is cryotherapy which results in a reduction of tissue temperature by the withdrawal of heat from the body. Cryotherapy is advantageous because of its ability to reduce tissue temperature at the site of muscle damage. However, there are logistical limitations to traditional cryotherapy modalities, such as cold-water immersion or whole-body cryotherapy, because they are limited by the duration for which they can be administered in a single dose. Phase change material (PCM) at a temperature of 15°C can deliver a single dose of cooling for a prolonged duration in a practical, efficacious, and safe way; hence overcoming the limitations of traditional cryotherapy modalities. Recently, 15°C PCM has been locally administered following isolated eccentric exercise, a soccer match, and baseball pitching, for durations of 3-6 h with no adverse effects. These data showed that using 15°C PCM to prolong the duration of cooling successfully reduced strength loss and soreness following exercise. Extending the positive effects associated with cryotherapy by prolonging the duration of cooling can enhance recovery following exercise and give athletes a competitive advantage.

Clinical Practice Guidelines for Pain Management in Acute Musculoskeletal Injury

PURPOSE

We aimed to produce comprehensive guidelines and recommendations that can be utilized by orthopaedic practices as well as other specialties to improve the management of acute pain following musculoskeletal injury.

METHODS

A panel of 15 members with expertise in orthopaedic trauma, pain management, or both was convened to review the literature and develop recommendations on acute musculoskeletal pain management. The methods described by the Grading of Recommendations Assessment, Development, and Evaluation Working Group were applied to each recommendation. The guideline was submitted to the Orthopaedic Trauma Association (OTA) for review and was approved on October 16, 2018.

RESULTS

We present evidence-based best practice recommendations and pain medication recommendations with the hope that they can be utilized by orthopaedic practices as well as other specialties to improve the management of acute pain following musculoskeletal injury. Recommendations are presented regarding pain management, cognitive strategies, physical strategies, strategies for patients on long term opioids at presentation, and system implementation strategies. We recommend the use of multimodal analgesia, prescribing the lowest effective immediate-release opioid for the shortest period possible, and considering regional anesthesia. We also recommend connecting patients to psychosocial interventions as indicated and considering anxiety reduction strategies such as aromatherapy. Finally, we also recommend physical strategies including ice, elevation, and transcutaneous electrical stimulation. Prescribing for patients on long term opioids at presentation should be limited to one prescriber. Both pain and sedation should be assessed regularly for inpatients with short, validated tools. Finally, the group supports querying the relevant regional and state prescription drug monitoring program, development of clinical decision support, opioid education efforts for prescribers and patients, and implementing a department or organization pain medication prescribing strategy or policy.

CONCLUSIONS

Balancing comfort and patient safety following acute musculoskeletal injury is possible when utilizing a true multimodal approach including cognitive, physical, and pharmaceutical strategies. In this guideline, we attempt to provide practical, evidence-based guidance for clinicians in both the operative and non-operative settings to address acute pain from musculoskeletal injury. We also organized and graded the evidence to both support recommendations and identify gap areas for future research.

The effect of varying degrees of compression from elastic vs plastic wrap on quadriceps intramuscular temperature during wetted ice application

The aim of this study was to evaluate and compare the effectiveness of wetted ice bag, applied with high compression elastic wrap or held in place with low compression plastic wrap, on reducing vastus lateralis intramuscular temperature and skin surface temperature. Ten healthy male participants had wetted ice packs applied to a standardized area on the anterior aspect of the quadriceps simultaneously to both legs for 30 minutes. The ice pack was secured with high compression (elastic wrap) to the left anterior thigh (60.6 ± 8.1 mm Hg) and low compression (plastic wrap) to the right anterior thigh (15.5 ± 4.0 mm Hg). Intramuscular temperature (1 and 3 cm) and skin temperature of the vastus lateralis were measured continuously during a 10-minute baseline period, 30-minute treatment period, and a 60-minute recovery period. No difference was observed between treatments in terms of the magnitude of reduction in intramuscular temperature at both 1 and 3 cm and skin temperature regardless of compression pressure (P > 0.05). Temperature upon conclusion of elastic wrap treatment was as follows: 17.8 ± 5.2°C at 1 cm and 23.1 ± 4.9°C at 3 cm; plastic wrap treatment: 17.9 ± 4.4°C at 1 cm and 24.5 ± 6.7°C at 3 cm. Plastic wraps may offer a practical alternative to elastic wraps for clinicians as they may be disposed of by the patient or athlete without having to stay at the treatment facility.

Arteriovenous Graft for Hemodialysis: Effect of Cryotherapy on Postoperative Pain and Edema

BACKGROUND

Arteriovenous grafting offers an alternative for patients whose vessels are unsuitable for arteriovenous fistula. However, as a result of subcutaneous tunnel dissection, postoperative pain and edema of the operated limb present early after surgery. As a traditional therapeutic approach, cryotherapy has the ability to suppress postoperative pain and edema.

AIMS

The purpose of the study was to investigate the feasibility of cryotherapy after arteriovenous graft surgery to decrease perioperative medication usage.

DESIGN

This study was a randomized controlled trial.

SETTING

A large integrated health care facility in South China.

PARTICIPANTS/SUBJECTS

A total of 85 hemodialysis patients who received arteriovenous graft surgery from March 2011 to February 2017 were enrolled.

METHODS

The participants were divided into an intervention group and a control group according to the postoperative management. Ice packs were applied covering the operative forearm for 120 minutes after wound closure in the intervention group. General information, pain score, analgesic consumption, wound inflammation, forearm edema, and participant satisfaction were compared between the two groups.

RESULTS

Cryotherapy-treated patients required less analgesia (26.19% vs. 48.84%, p < .05), reported lower pain score from 30 minutes to 48 hours postoperative (p < .05), less wound inflammation (11.90% vs. 25.58%, p < .05), and higher participant satisfaction (8.92 ± 0.57 vs. 6.52 ± 0.63, p < .05), whereas the incidence of forearm edema was equivalent (p > .05). No adverse events were reported in either group.

CONCLUSIONS

Cryotherapy is a preferable intervention for patients after arteriovenous graft implantation as a result of its favorable cost, convenience, and fewer side effects.

Continuous-flow cryocompression therapy penetrates to bone level in hip fracture patients in a numerical simulation

BACKGROUND

The aim of this study was to define deep tissue temperature during cryotherapy in postoperative hip fracture patients, by using measured skin temperature as input parameter for a simple numerical model. Second, an association was investigated between pain and tissue temperature distribution, to assess cryotherapy-induced analgesia of soft tissue-derived pain.

METHODS

Data from 35 participants in an ongoing trial was used. In three subjects who consented on optional measurements, skin temperature was measured in 3 days during and after cryotherapy. A simple numerical model was developed to calculate tissue temperature distribution during cryotherapy.

RESULTS

Inter and intrasubject skin temperature displayed high variation: trochanter 11-27 °C, mid-femur 11-24 °C, distal femur 10-16 °C. Predicted temperatures decreased to 20 °C at 1 cm, 26 °C at 2 cm, and 30 °C at 3 cm tissue depth. Smallest soft tissue layer was measured at the trochanter; 42% had less than 30 mm and 21% had less than 20 mm. Numeric rating scale pain varied (mean = 2.14; SD = 1.92), and no association was found between pain and decrease in temperature (r = 0.064; p = 0.204).

CONCLUSIONS

Cryotherapy was predicted to reduce temperature up to 3 cm; in cachectic patients, this reaches the bone, where it might have implications for bone tissue healing when treated for a prolonged period of time. Cryotherapy-induced analgesia is likely to originate from skin analgesia rather than analgesia of muscle or bone-derived pain.

The Effect of Elevation on Intramuscular Tissue Temperatures

Context: Ice, compression, and elevation, or ICE, is a widely used treatment for acute musculoskeletal injuries. The effects of ice and compression on tissue temperatures have been established, but whether elevation during cryotherapy affects temperature change has not. Elevation has potential to alter local perfusion and thereby alter the balance of heat loss/heat gain, potentially impacting tissue cooling during cryotherapy. Objective: To measure the effect and interaction of ice, compression, and elevation on intramuscular temperatures. We hypothesized that elevation would not have an effect on intramuscular tissue temperature. Design: Randomized crossover study design. Setting: University athletic training facility. Patients or Other Participants: A total of 15 healthy volunteers (age 20.93 [1.67] y) provided informed consent and participated. Interventions: Participants completed 8 treatment conditions: no treatment (control), ice only (I), compression only (C), elevation only (E), ice and compression (IC), ice and elevation (IE), compression and elevation (CE), or ice, compression, and elevation (ICE). All conditions were tested on each participant with a minimum of 48 hours between each condition. Intramuscular temperatures were recorded every 30 seconds during a 1-minute preapplication, 30-minute treatment, and 20-minute postapplication period. Main Outcome Measures: The temperature difference between the mean treatment temperature and the mean preapplication temperature was compared across each measurement depth and treatment condition. Results: Non-ice treatments (control, C, E, and CE; means 33.4, 34.5, 33.7, and 34.6, respectively) had warmer intramuscular temperatures than any treatment that included ice (I, IC, IE, and ICE; means 28.4, 19.8, 28.0, and 19.3, respectively). There were no differences between IC and ICE (means 19.8 and 19.3, respectively). Ice alone was different from everything (Control, C, E, IC, CE, and ICE) except IE Conclusions: Elevation does not appear to play a role in temperature changes during cryotherapy treatments.

Effects of Topical Icing on Inflammation, Angiogenesis, Revascularization, and Myofiber Regeneration in Skeletal Muscle Following Contusion Injury

Contusion injuries in skeletal muscle commonly occur in contact sport and vehicular and industrial workplace accidents. Icing has traditionally been used to treat such injuries under the premise that it alleviates pain, reduces tissue metabolism, and modifies vascular responses to decrease swelling. Previous research has examined the effects of icing on inflammation and microcirculatory dynamics following muscle injury. However, whether icing influences angiogenesis, collateral vessel growth, or myofiber regeneration remains unknown. We compared the effects of icing vs. a sham treatment on the presence of neutrophils and macrophages; expression of CD34, von Willebrands factor (vWF), vascular endothelial growth factor (VEGF), and nestin; vessel volume; capillary density; and myofiber regeneration in skeletal after muscle contusion injury in rats. Muscle tissue was collected 1, 3, 7, and 28 d after injury. Compared with uninjured rats, muscles in rats that sustained the contusion injury exhibited major necrosis, inflammation, and increased expression of CD34, vWF, VEGF, and nestin. Compared with the sham treatment, icing attenuated and/or delayed neutrophil and macrophage infiltration; the expression of vWF, VEGF, and nestin; and the change in vessel volume within muscle in the first 7 d after injury (P < 0.05). By contrast, icing did not influence capillary density in muscle 28 d after injury (P = 0.59). The percentage of immature myofibers relative to the total number of fibers was greater in the icing group than in the sham group 28 d after injury (P = 0.026), but myofiber cross-sectional area did not differ between groups after 7 d (P = 0.35) and 28 d (P = 0.30). In conclusion, although icing disrupted inflammation and some aspects of angiogenesis/revascularization, these effects did not result in substantial differences in capillary density or muscle growth.

The efficacy of continuous-flow cryo and cyclic compression therapy after hip fracture surgery on postoperative pain: design of a prospective, open-label, parallel, multicenter, randomized controlled, clinical trial

BACKGROUND

The number of hip fractures and resulting post-surgical outcome are a major public health concern and the incidence is expected to increase significantly. The acute recovery phase after hip fracture surgery in elder patients is often complicated by severe pain, high morphine consumption, perioperative blood loss with subsequent transfusion and delirium. Postoperative continuous-flow cryocompression therapy is suggested to minimize these complications and to attenuate the inflammatory reaction that the traumatic fracture and subsequent surgical trauma encompass. Based on a pilot study in patients undergoing total hip arthroplasty for osteoarthritis, it is anticipated that patients treated with continuous-flow cryocompression therapy will have less pain, less morphine consumption and lower decrease of postoperative hemoglobin levels. These factors are associated with a shorter hospital stay and better long-term (functional) outcome.

METHODS/DESIGN

One hundred and sixty patients with an intra or extracapsular hip fracture scheduled for internal fixation (intramedullary hip nail, dynamic hip screw or cannulated screws) or prosthesis surgery (total hip or hemiarthroplasty) will be included in this prospective, open-label, parallel, multicenter, randomized controlled, clinical superiority trial. Patients will be allocated to two treatment arms: group 'A' will be treated with continuous-flow cryocompression therapy and compared to group 'B' that will receive standard care. Routine use of drains and/or compressive bandages is allowed in both groups. The primary objective of this study is to compare acute pain the first 72 h postoperative, measured with numeric rating scale for pain. Secondary objectives are: (non-) morphine analgesic use; adjusted postoperative hemoglobin level; transfusion incidence; incidence, duration and severity of delirium and use of psychotropic medication; length of stay; location and duration of rehabilitation; functional outcome; short-term patient-reported health outcome; general and cryotherapy related complications and feasibility.

DISCUSSION

This is the first randomized controlled trial that will assess the analgesic efficiacy of continuous-flow cryocompression therapy in the acute recovery phase after hip fracture surgery.

TRIAL REGISTRATION

www.trialregister.nl, NTR4152 (23(rd) of August 2013).

Current concepts on burn wound conversion-A review of recent advances in understanding the secondary progressions of burns

Burn wound conversion describes the process by which superficial partial thickness burns convert into deeper burns necessitating surgical intervention. Fully understanding and thus controlling this phenomenon continues to defy burn surgeons. However, potentially guiding burn wound progression so as to obviate the need for surgery while still bringing about healing with limited scarring is the major unmet challenge. Comprehending the pathophysiologic background contributing to deeper progression of these burns is an essential prerequisite to planning any intervention. In this study, a review of articles examining burn wound progression over the last five years was conducted to analyze trends in recent burn progression research, determine changes in understanding of the pathogenesis of burn conversion, and subsequently examine the direction for future research in developing therapies. The majority of recent research focuses on applying therapies from other disease processes to common underlying pathogenic mechanisms in burn conversion. While ischemia, inflammation, and free oxygen radicals continue to demonstrate a critical role in secondary necrosis, novel mechanisms such as autophagy have also been shown to contribute affect significantly burn progression significantly. Further research will have to determine whether multiple mechanisms should be targeted when developing clinical therapies.

Induced hypothermia during resuscitation from hemorrhagic shock attenuates microvascular inflammation in the rat mesenteric microcirculation

Microvascular inflammation occurs during resuscitation following hemorrhagic shock, causing multiple organ dysfunction and mortality. Preclinical evidence suggests that hypothermia may have some benefit in selected patients by decreasing this inflammation, but this effect has not been extensively studied. Intravital microscopy was used to visualize mesenteric venules of anesthetized rats in real time to evaluate leukocyte adherence and mast cell degranulation. Animals were randomly allocated to normotensive or hypotensive groups and further subdivided into hypothermic and normothermic resuscitation (n = 6 per group). Animals in the shock groups underwent mean arterial blood pressure reduction to 40 to 45 mmHg for 1 h via blood withdrawal. During the first 2 h following resuscitation by infusion of shed blood plus double that volume of normal saline, rectal temperature of the hypothermic groups was maintained at 32°C to 34°C, whereas the normothermic groups were maintained between 36°C to 38°C. The hypothermic group was then rewarmed for the final 2 h of resuscitation. Leukocyte adherence was significantly lower after 2 h of hypothermic resuscitation compared with normothermic resuscitation: (2.8 ± 0.8 vs. 8.3 ± 1.3 adherent leukocytes, P = 0.004). Following rewarming, leukocyte adherence remained significantly different between hypothermic and normothermic shock groups: (4.7 ± 1.2 vs. 9.5 ± 1.6 adherent leukocytes, P = 0.038). Mast cell degranulation index (MDI) was significantly decreased in the hypothermic (1.02 ± 0.04 MDI) versus normothermic (1.22 ± 0.07 MDI) shock groups (P = 0.038) after the experiment. Induced hypothermia during resuscitation following hemorrhagic shock attenuates microvascular inflammation in rat mesentery. Furthermore, this decrease in inflammation is carried over after rewarming takes place.

Modulating exercise-induced hormesis: Does less equal more?

Hormesis encompasses the notion that low levels of stress stimulate or upregulate existing cellular and molecular pathways that improve the capacity of cells and organisms to withstand greater stress. This notion underlies much of what we know about how exercise conditions the body and induces long-term adaptations. During exercise, the body is exposed to various forms of stress, including thermal, metabolic, hypoxic, oxidative, and mechanical stress. These stressors activate biochemical messengers, which in turn activate various signaling pathways that regulate gene expression and adaptive responses. Historically, antioxidant supplements, nonsteroidal anti-inflammatory drugs, and cryotherapy have been favored to attenuate or counteract exercise-induced oxidative stress and inflammation. However, reactive oxygen species and inflammatory mediators are key signaling molecules in muscle, and such strategies may mitigate adaptations to exercise. Conversely, withholding dietary carbohydrate and restricting muscle blood flow during exercise may augment adaptations to exercise. In this review article, we combine, integrate, and apply knowledge about the fundamental mechanisms of exercise adaptation. We also critically evaluate the rationale for using interventions that target these mechanisms under the overarching concept of hormesis. There is currently insufficient evidence to establish whether these treatments exert dose-dependent effects on muscle adaptation. However, there appears to be some dissociation between the biochemical/molecular effects and functional/performance outcomes of some of these treatments. Although several of these treatments influence common kinases, transcription factors, and proteins, it remains to be determined if these interventions complement or negate each other, and whether such effects are strong enough to influence adaptations to exercise.

Whole-body cryotherapy: empirical evidence and theoretical perspectives

Whole-body cryotherapy (WBC) involves short exposures to air temperatures below −100°C. WBC is increasingly accessible to athletes, and is purported to enhance recovery after exercise and facilitate rehabilitation postinjury. Our objective was to review the efficacy and effectiveness of WBC using empirical evidence from controlled trials. We found ten relevant reports; the majority were based on small numbers of active athletes aged less than 35 years. Although WBC produces a large temperature gradient for tissue cooling, the relatively poor thermal conductivity of air prevents significant subcutaneous and core body cooling. There is weak evidence from controlled studies that WBC enhances antioxidant capacity and parasympathetic reactivation, and alters inflammatory pathways relevant to sports recovery. A series of small randomized studies found WBC offers improvements in subjective recovery and muscle soreness following metabolic or mechanical overload, but little benefit towards functional recovery. There is evidence from one study only that WBC may assist rehabilitation for adhesive capsulitis of the shoulder. There were no adverse events associated with WBC; however, studies did not seem to undertake active surveillance of predefined adverse events. Until further research is available, athletes should remain cognizant that less expensive modes of cryotherapy, such as local ice-pack application or cold-water immersion, offer comparable physiological and clinical effects to WBC.

Therapeutic modalities--an updated review for the hand surgeon

The number of therapeutic modalities available to the hand surgeon has greatly increased over the past several decades. A field once predicated only on heat, massage, and cold therapy now uses electrical stimulators, ultrasound, biofeedback, iontophoresis, phonophoresis, mirror therapy, lasers, and a number of other modalities. With this expansion in choices, there has been a concurrent effort to better define which modalities are truly effective. In this review, we aim to characterize the commonly used modalities and provide the evidence available that supports their continued use.

Physiological and nutritional aspects of post-exercise recovery: specific recommendations for female athletes

Gender-based differences in the physiological response to exercise have been studied extensively for the last four decades, and yet the study of post-exercise, gender-specific recovery has only been developing in more recent years. This review of the literature aims to present the current state of knowledge in this field, focusing on some of the most pertinent aspects of physiological recovery in female athletes and how metabolic, thermoregulatory, or inflammation and repair processes may differ from those observed in male athletes. Scientific investigations on the effect of gender on substrate utilization during exercise have yielded conflicting results. Factors contributing to the lack of agreement between studies include differences in subject dietary or training status, exercise intensity or duration, as well as the variations in ovarian hormone concentrations between different menstrual cycle phases in female subjects, as all are known to affect substrate metabolism during sub-maximal exercise. If greater fatty acid mobilization occurs in females during prolonged exercise compared with males, the inverse is observed during the recovery phase. This could explain why, despite mobilizing lipids to a greater extent than males during exercise, females lose less fat mass than their male counterparts over the course of a physical training programme. Where nutritional strategies are concerned, no difference appears between males and females in their capacity to replenish glycogen stores; optimal timing for carbohydrate intake does not differ between genders, and athletes must consume carbohydrates as soon as possible after exercise in order to maximize glycogen store repletion. While lipid intake should be limited in the immediate post-exercise period in order to favour carbohydrate and protein intake, in the scope of the athlete's general diet, lipid intake should be maintained at an adequate level (30%). This is particularly important for females specializing in long-duration events. With protein balance, it has been shown that a negative nitrogen balance is more often observed in female athletes than in male athletes. It is therefore especially important to ensure that this remains the case during periods of caloric restriction, especially when working with female athletes showing a tendency to limit their caloric intake on a daily basis. In the post-exercise period, females display lower thermolytic capacities than males. Therefore, the use of cooling recovery methods following exercise, such as cold water immersion or the use of a cooling vest, appear particularly beneficial for female athletes. In addition, a greater decrease in arterial blood pressure is observed after exercise in females than in males. Given that the return to homeostasis after a brief intense exercise appears linked to maintaining good venous return, it is conceivable that female athletes would find a greater advantage to active recovery modes than males. This article reviews some of the major gender differences in the metabolic, inflammatory and thermoregulatory response to exercise and its subsequent recovery. Particular attention is given to the identification of which recovery strategies may be the most pertinent to the design of training programmes for athletic females, in order to optimize the physiological adaptations sought for improving performance and maintaining health.

Neutrophil responses to injury or inflammation impair peripheral gustatory function

The adult peripheral taste system is capable of extensive functional plasticity after injury. Sectioning the chorda tympani (CT), a primary sensory afferent nerve, elicits transient changes in the uninjured, contralateral population of taste receptor cells. Remarkably, the deficits are specific to the sodium transduction pathway. Normal function is quickly restored in the intact nerve, in parallel with an influx of macrophages to both the denervated and uninjured sides of the tongue. However, changing the dietary environment by restricting sodium blocks the macrophage response and prolongs functional alterations. Since the functional deficits occur before macrophages are present in the peripheral taste system, we hypothesized that neutrophils play a role in modulating neural responses in the intact CT. First, the dynamics of the neutrophil response to nerve injury were analyzed in control-fed and sodium-deficient rats. Nerve sectioning briefly increased the number of neutrophils on both the denervated and uninjured sides of the tongue. The low-sodium diet amplified and extended the bilateral neutrophil response to injury, in parallel with the persistent changes in sodium taste function. To test the impact of neutrophils on taste function, we depleted these cells prior to nerve sectioning and recorded neural responses from the intact CT. This treatment restored normal sodium responses in the uninjured nerve. Moreover, recruiting neutrophils to the tongue induced deficits in sodium taste function in both CT nerves. Neutrophils play a critical role in ongoing inflammatory responses in the oral cavity, and may induce changes in taste perception. We also suggest that balanced neutrophil and macrophage responses enable normal neural responses after neural injury.

The inflammatory response to skeletal muscle injury: illuminating complexities

Injury of skeletal muscle, and especially mechanically induced damage such as contusion injury, frequently occurs in contact sports, as well as in accidental contact sports, such as hockey and squash. The large variations with regard to injury severity and affected muscle group, as well as non-specificity of reported symptoms, complicate research aimed at finding suitable treatments. Therefore, in order to increase the chances of finding a successful treatment, it is important to understand the underlying mechanisms inherent to this type of skeletal muscle injury and the cellular processes involved in muscle healing following a contusion injury. Arguably the most important of these processes is inflammation since it is a consistent and lasting response. The inflammatory response is dependent on two factors, namely the extent of actual physical damage and the degree of muscle vascularization at the time of injury. However, long-term anti-inflammatory treatment is not necessarily effective in promoting healing, as indicated by various studies on NSAID treatment. Because of the factors named earlier, human studies on the inflammatory response to contusion injury are limited, but several experimental animal models have been designed to study muscle damage and regeneration. The early recovery phase is characterized by the overlapping processes of inflammation and occurrence of secondary damage. Although neutrophil infiltration has been named as a contributor to the latter, no clear evidence exists to support this claim. Macrophages, although forming part of the inflammatory response, have been shown to have a role in recovery, rather than in exacerbating secondary damage. Several probable roles for this cell type in the second phase of recovery, involving resolution processes, have been identified and include the following: (i) phagocytosis to remove cellular debris; (ii) switching from a pro- to anti-inflammatory phenotype in regenerating muscle; (iii) preventing muscle cells from undergoing apoptosis; (iv) releasing factors to promote muscle precursor cell activation and growth; and (v) secretion of cytokines and growth factors to facilitate vascular and muscle fibre repair. These many different roles suggest that a single treatment with one specific target cell population (e.g. neutrophils, macrophages or satellite cells) may not be equally effective in all phases of the post-injury response. To find the optimal targeted, but time-course-dependent, treatments requires substantial further investigations. However, the techniques currently used to induce mechanical injury vary considerably in terms of invasiveness, tools used to induce injury, muscle group selected for injury and contractile status of the muscle, all of which have an influence on the immune and/or cytokine responses. This makes interpretation of the complex responses more difficult. After our review of the literature, we propose that a standardized non-invasive contusion injury is the ideal model for investigations into the immune responses to mechanical skeletal muscle injury. Despite its suitability as a model, the currently available literature with respect to the inflammatory response to injury using contusion models is largely inadequate. Therefore, it may be premature to investigate highly targeted therapies, which may ultimately prove more effective in decreasing athlete recovery time than current therapies that are either not phase-specific, or not administered in a phase-specific fashion.

Extended (16-hour) tourniquet application after combat wounds: a case report and review of the current literature

We present a case of emergency tourniquet use of unusually long duration. The patient was wounded during combat operations, and the subsequent battle and evacuation caused a significant delay in surgical treatment of his wounds. Emergency tourniquets can be lifesaving, but are not benign interventions. In general, the extent of tourniquet injury increases with increasing time of application. Despite having a tourniquet in place for 16 hours, the limb was salvaged and significant functional recovery was accomplished. We conducted a search of the published literature including the Medline database, and present a review of the relevant articles concerning emergency tourniquet use, tourniquet injury, and mitigating treatments. Given the widespread use of tourniquets in ongoing military operations, it seems likely that tourniquets will transition to civilian use. Thus it is important for physicians to understand tourniquet injury and appreciate that even extended tourniquet application times does not necessarily doom the affected limb.