Remote Effects of Electromagnetic Millimeter Waves on Experimentally Induced Cold Pain: A Double-Blinded Crossover Investigation in Healthy Volunteers.

BACKGROUND: The hypoalgesic effect of electromagnetic millimeter waves (MW) is well studied in animal model; however, the results of human research are controversial. The aim of this study was to evaluate the effects of various frequency ranges of MW on hypoalgesia using the cold pressor test (CPT). METHODS: Experimental pain was induced using standardized CPT protocols in 20 healthy male volunteers. The skin of the lower part of sternum was exposed to MW with a frequency of 42.25 GHz (active generator); MW within 50-75 GHz frequency range (noise generator); or an inactive MW device (placebo generator) in a random crossover double-blinded manner. Pain threshold, measured using the CPT, was the primary outcome. Other CPT parameters, heart rate, blood pressure, incidence of subjective sensations (paresthesia) during exposure, as well as quality of volunteers' blinding were also recorded. The end points of the condition with exposure to 42.25 GHz, were compared with baseline; exposure to noise 50-75 GHz; and placebo generators. RESULTS: Pain threshold increased during exposure to the 42.25 GHz generator when compared with baseline: median difference (MD), 1.97 seconds (95% confidence interval [CI], 0.35-3.73) and noise generator: MD, 1.27 seconds (95% CI, 0.05-2.33) but not compared with the placebo generator. Time to onset of cold and increasing pain sensations as well as diastolic blood pressure increased under the exposure to the 42.25 GHz generator when compared with baseline and noise generator. Other outcome measures were comparable among the study conditions. CONCLUSIONS: We were able to partially confirm the previously suggested hypoalgesic effects of low-intensity electromagnetic MW. However, the effect was indistinguishable from the placebo condition in our investigation.

Clinical validity of the nerve root sedimentation sign in patients with suspected lumbar spinal stenosis.

BACKGROUND CONTEXT: The nerve root sedimentation sign in transverse magnetic resonance imaging has been shown to discriminate well between selected patients with and without lumbar spinal stenosis (LSS), but the performance of this new test, when used in a broader patient population, is not yet known. PURPOSE: To evaluate the clinical performance of the nerve root sedimentation sign in detecting central LSS above L5 and to determine its potential significance for treatment decisions. STUDY DESIGN: Retrospective cohort study. PATIENT SAMPLE: One hundred eighteen consecutive patients with suspected LSS (52% women, median age 62 years) with a median follow-up of 24 months. OUTCOME MEASURES: Oswestry disability index (ODI) and back and leg pain relief. METHODS: We performed a clinical test validation study to assess the clinical performance of the sign by measuring its association with health outcomes. Subjects were patients referred to our orthopedic spine unit from 2004 to 2007 before the sign had been described. Based on clinical and radiological diagnostics, patients had been treated with decompression surgery or nonsurgical treatment. Changes in the ODI and pain from baseline to 24-month follow-up were compared between sedimentation sign positives and negatives in both treatment groups. RESULTS: Sixty-nine patients underwent surgery. Average baseline ODI in the surgical group was 54.7%, and the sign was positive in 39 patients (mean ODI improvement 29.0 points) and negative in 30 (ODI improvement 28.4), with no statistically significant difference in ODI and pain improvement between groups. In the 49 patients of the nonsurgical group, mean baseline ODI was 42.4%; the sign was positive in 18 (ODI improvement 0.6) and negative in 31 (ODI improvement 17.7). A positive sign was associated with a smaller ODI and back pain improvement than negative signs (both p<.01 on t test). CONCLUSIONS: In patients commonly treated with decompression surgery, the sedimentation sign does not appear to predict surgical outcome. In nonsurgically treated patients, a positive sign is associated with more limited improvement. In these cases, surgery might be effective, but this needs investigation in prospective randomized trials (Australian New Zealand Clinical Trial Registry, number ACTRN12610000567022).

Blunt Criterion trauma model for head and chest injury risk assessment of cal. 380 R and cal. 22 long blank cartridge actuated gundog retrieval devices.

BACKGROUND: Blunt ballistic impact trauma is a current research topic due to the widespread use of kinetic energy munitions in law enforcement. In the civilian setting, an automatic dummy launcher has recently been identified as source of blunt impact trauma. However, there is no data on the injury risk of conventional dummy launchers. It is the aim of this investigation to predict potential impact injury to the human head and chest on the basis of the Blunt Criterion which is an energy based blunt trauma model to assess vulnerability to blunt weapons, projectile impacts, and behind-armor-exposures. METHODS: Based on experimentally investigated kinetic parameters, the injury risk of two commercially available gundog retrieval devices (Waidwerk Telebock, Germany; Turner Richards, United Kingdom) was assessed using the Blunt Criterion trauma model for blunt ballistic impact trauma to the head and chest. RESULTS: Assessing chest impact, the Blunt Criterion values for both shooting devices were higher than the critical Blunt Criterion value of 0.37, which represents a 50% risk of sustaining a thoracic skeletal injury of AIS 2 (moderate injury) or AIS 3 (serious injury). The maximum Blunt Criterion value (1.106) was higher than the Blunt Criterion value corresponding to AIS 4 (severe injury). With regard to the impact injury risk to the head, both devices surpass by far the critical Blunt Criterion value of 1.61, which represents a 50% risk of skull fracture. Highest Blunt Criterion values were measured for the Turner Richards Launcher (2.884) corresponding to a risk of skull fracture of higher than 80%. CONCLUSION: Even though the classification as non-guns by legal authorities might implicate harmlessness, the Blunt Criterion trauma model illustrates the hazardous potential of these shooting devices. The Blunt Criterion trauma model links the laboratory findings to the impact injury patterns of the head and chest that might be expected.

Mind your hand during the energy crunch: Functional Outcome of Circular Saw Hand Injuries.

BACKGROUND: Although injuries due to circular saws are very common all over the world, there is surprisingly little information available about their functional outcomes. As the socioeconomic impact of these injuries is immense and determined by the casualties' disability and impairment, it is the objective of this study to present data on the functional outcome, disability, and impairment of hand injuries due to electric circular saws. METHODS: Patients treated from 1999 through 2007 for circular saw-related hand injuries were contacted and asked for clinical follow-up assessment. The clinical follow-up protocol consisted of a physical examination and an assessment of static muscle power (grip and pinch strength). For assessment of the subjective experience of the patients regarding their injury-related disability and impairment, the DASH follow-up questionnaire was used. The occupational impact of these injuries was measured by number of lost working days. Finally, safety-related behaviour of the patients was investigated. RESULTS: 114 Patients were followed-up on average 52 months after the injury. Average in-house treatment was 8.8 days. Average time lost from work was 14.8 weeks. A significant reduction of static muscle testing parameters compared with the uninjured hand was revealed for grip strength, tip pinch, key pinch, and palmar pinch. Average DASH score was 17.4 (DASH work 15.8, DASH sports/music 17.7). Most patients had more than ten years experience in using these power tools. CONCLUSION: The everyday occurrence of circular saw-related hand injuries followed by relatively short periods of in-house treatment might distort the real dimension of the patients' remaining disability and impairment. While the trauma surgeon's view is generally confined to the patients' clinical course, the outcome parameters in this follow-up investigation, with loss of working time as the key factor, confirm that the whole socioeconomic burden is much greater than the direct cost of treatment.

Noise trauma induced by a mousetrap--sound pressure level measurement of vole captive bolt devices.

While ballistic parameters of vole captive bolt devices have been reported, there is no investigation on their hazardous potential to cause noise trauma. The aim of this experimental study was to measure the sound pressure levels of vole captive bolt devices. Two different shooting devices were examined with a modular precision sound level meter on an outdoor firing range. Measurements were taken in a semi-circular configuration with measuring points 0 degrees in front of the muzzle, 90 degrees at right angle of the muzzle, and 180 degrees behind the shooting device. Distances between muzzle and microphone were 0.5, 1, 2, 10, and 20 m. Sound pressure levels exceeded 130 dB(C) at any measuring point within the 20-m area. Highest measurements (more than 172 dB[C]) were taken in the 0 degrees direction at the 0.5-m distance for both shooting devices proving the hazardous potential of these gadgets to cause noise trauma.

Accidental circular saw hand injuries: trauma mechanisms, injury patterns, and accident insurance.

INTRODUCTION: Hand injuries due to circular saws are a common reason for patients seeking medical care in emergency departments. With respect to cases of insurance fraud, these injuries are of medico-legal interest. It is the aim of this study to investigate the critical circumstances of the incidents, the accident mechanism, and the specific injury patterns of circular saw related hand injuries with regard to accident insurance coverage. PATIENTS AND METHODS: Circular saw related hand injuries for the years 1999 through 2007 were followed-up and assessed in detail. Type, severity and pattern of the injury were assessed. An accident analysis investigated characteristic of the activities, of the saws, of the stock/cutting material, operational activities of the operators prior to/at the time of the incident, and detailed information on the insurance status. RESULTS: The follow-up study encompassed 114 patients. A majority of these were covered by private or statutory accident insurances. Compensation payments were made in all cases. All lesions involved one hand, mainly the left non-dominant hand. Thumb and index were at highest risk for injury. One-finger injuries occurred mainly at the middle or distal phalanx. With increasing number of affected fingers, the level of the injury moved closer to the proximal phalanx. A majority of injuries occurred during do-it-yourself activities. Among blade contact injuries, the so-called kickback-mechanism was at highest risk. CONCLUSION: Positive circumstantial indications of a self-inflicted injury, which are often cited in the literature are less conclusive for the medico-legal decision finding. The detailed anatomic description of any lesions and the alleged accident mechanism as initially described by the patients in the emergency setting is the basis for any later accident reconstruction.

Proper estimation of blood loss on scene of trauma: tool or tale?

BACKGROUND: Visually estimated amount of blood loss may influence decision making in the prehospital setting. The purpose of this study was to determine the ability and accuracy of paramedics and emergency physicians to visually estimate a volume of external blood loss and the influence of different vital signs. METHODS: In a prospective, blinded, observational design, participants were asked to visually estimate the amount of blood in six simulated trauma scenarios. Casualties were provided with a simulated injury, and a certain amount of artificial blood that was poured on the casualties' clothing and on the floor. In addition, vital signs (i.e., blood pressure and heart rate) were given. Each two moulage patients were provided with the same injury pattern and the same simulated blood loss. Although one patient seemed to be normovolemic, the other seemed to be hypovolemeic by the given vital signs. RESULTS: With regard to all given amounts of blood loss, providing vital parameters suggesting instability (i.e., low blood pressure, high heart rate) led to a higher estimation of the lost blood volume in both paramedics and emergency physicians. However, estimations were influenced impressively by the given parameters. For both stable and unstable patients, small actual volumes were overestimated, whereas higher volumes tended to be underestimated. Neither occupational status (emergency physician or paramedic) nor gender or level of experience influenced accuracy of estimated blood loss significantly.

Millimetre wave therapy for pain relief after total knee arthroplasty: a randomised controlled trial.

Millimetre wave therapy (MWT) is a promising complementary method for pain relief, however rigorous investigations of its effectiveness are needed. The purpose of this study was to examine if MWT can reduce opioid requirement compared to sham procedure applied for relief of acute pain in patients after total knee arthroplasty (TKA). Eighty patients undergoing TKA were randomly assigned to receive MWT or sham procedure. Patients and evaluators were blinded to the group allocation. MWT consisted of six sessions, each session of 30 min duration. During each session the knee wound was exposed to electromagnetic waves with frequency 50-75 GHz and power density 4.2 mW/cm(2). Postoperative analgesia with piritramide, a weak opioid with 0.7 potency of morphine delivered via patient-controlled analgesia pump, was directed to achieve pain intensity of less than 40 on a 100 mm visual analogue scale (VAS). The primary outcome measure was postoperative piritramide requirement for three days after surgery. Secondary outcome measures were: total ibuprofen requirement from the fourth postoperative day to discharge; success of patients' blinding; patients' satisfaction with pain relief; incidence of analgesia-related side effects; heart rate and blood pressure. Piritramide requirement was similar in both groups whereby all patients reported adequate pain relief measured on a VAS. Secondary outcome measures were also comparable in both groups. The majority of patients in both groups believed they had received true MWT and wanted to repeat it in future. Millimetre waves applied to surfaces of surgical wounds did not reduce opioid requirement compared to the sham procedure after TKA.

Postmortem radiological investigation of bridging vein ruptures.

In the usual method of brain removal in forensic autopsies, the upper bridging veins were invariably torn. There are several types of head injuries, in which ruptures of these vessels are the predominant intracranial injury. For the past 5 years we have investigated nearly all cases of lethal head injuries by a simple X-ray method (axial X-ray after instillation of contrast material into the superior sagittal sinus). The evaluation of the 350 X-rays which were available until today can be summarized by the following statements. (a) Anatomy of the parasagittal bridging veins: regarding the numbers and diameters of the veins, we can separate cases with many bridging veins of small diameter from a group with few veins of a large diameter. (b) Causes of injury and direction of impact: bridging vein ruptures resulted more often from frontal than from occipital, parietal and lateral impacts and occurred in traffic accidents in the majority of our cases.