Electrocution Due to Fractal Wood Burning: Two Case Reports and a Review of the Medical Literature

ABSTRACT

Fractal wood burning is a new technique of pyrography that passes an electrical current through a piece of wood resulting in decorative electrical burns. This practice has become increasingly popular with many walk-through tutorials of the process found online. This includes videos of how to build homemade devices fashioned from disassembled microwave oven transformers. There have been 31 reported deaths and many serious injuries due to fractal wood burning resulting in news headlines, warning statements, and an outright ban of the practice at certain woodworking events. The medical community has begun to recognize the danger of fractal wood burning with a few cases of severe burn injuries reported. We report 2 cases of electrocution from fractal wood burning accidents. The scene investigations were examined, including the similarities in the homemade microwave oven transformers that were used, as well as the autopsy findings. The pathophysiology of fractal wood burning and the creation of Lichtenberg figures is discussed as well as the high-voltage injury patterns seen in cases of fractal wood burning accidents. Other cases of electrical injury from fractal wood burning accidents reported in the news and medical literature were then examined in terms of demographics, burn pattern, cardiac findings, and whether a homemade wood burning device was involved.

A Full-Thickness Burn in a Teenager Resulting from Prolonged Contact with a Mobile Phone Charging Cube: A Case Report

We present a case of a teenager who suffered a full-thickness burn following prolonged contact with a mobile phone charging cube. The patient required primary surgical excision and closure of the wound resulting in a good clinical outcome. There have been multiple reports in the literature of burns resulting from lithium batteries; however, this appears to be the first case report of a full thickness burn resulting from a mobile phone charging cube. Given the ubiquity of mobile phone use among teenagers, primary care providers should warn patients about the risks of sleeping with an electronic device while it is connected to a charger.

Low intensity transcranial electric stimulation: Safety, ethical, legal regulatory and application guidelines

Low intensity transcranial electrical stimulation (TES) in humans, encompassing transcranial direct current (tDCS), transcutaneous spinal Direct Current Stimulation (tsDCS), transcranial alternating current (tACS), and transcranial random noise (tRNS) stimulation or their combinations, appears to be safe. No serious adverse events (SAEs) have been reported so far in over 18,000 sessions administered to healthy subjects, neurological and psychiatric patients, as summarized here. Moderate adverse events (AEs), as defined by the necessity to intervene, are rare, and include skin burns with tDCS due to suboptimal electrode-skin contact. Very rarely mania or hypomania was induced in patients with depression (11 documented cases), yet a causal relationship is difficult to prove because of the low incidence rate and limited numbers of subjects in controlled trials. Mild AEs (MAEs) include headache and fatigue following stimulation as well as prickling and burning sensations occurring during tDCS at peak-to-baseline intensities of 1-2mA and during tACS at higher peak-to-peak intensities above 2mA. The prevalence of published AEs is different in studies specifically assessing AEs vs. those not assessing them, being higher in the former. AEs are frequently reported by individuals receiving placebo stimulation. The profile of AEs in terms of frequency, magnitude and type is comparable in healthy and clinical populations, and this is also the case for more vulnerable populations, such as children, elderly persons, or pregnant women. Combined interventions (e.g., co-application of drugs, electrophysiological measurements, neuroimaging) were not associated with further safety issues. Safety is established for low-intensity 'conventional' TES defined as <4mA, up to 60min duration per day. Animal studies and modeling evidence indicate that brain injury could occur at predicted current densities in the brain of 6.3-13A/m2 that are over an order of magnitude above those produced by tDCS in humans. Using AC stimulation fewer AEs were reported compared to DC. In specific paradigms with amplitudes of up to 10mA, frequencies in the kHz range appear to be safe. In this paper we provide structured interviews and recommend their use in future controlled studies, in particular when trying to extend the parameters applied. We also discuss recent regulatory issues, reporting practices and ethical issues. These recommendations achieved consensus in a meeting, which took place in Göttingen, Germany, on September 6-7, 2016 and were refined thereafter by email correspondence.

360-Degree Iris Burns Following Conductive Keratoplasty

PURPOSE

The authors report a case with multiple iris burns after conductive keratoplasty to correct hyperopia.

METHODS

Case report.

RESULTS

A 52-year-old woman with hyperopia had a previous conductive keratoplasty procedure and underwent a conductive keratoplasty re-treatment 6 months later. Postoperatively, she presented with 360-degree iris burns in both eyes that were correlated with the corneal conductive keratoplasty scars. In addition, specular microscopy revealed decreased endothelial cell density for both eyes.

CONCLUSIONS

This is the first reported case of iris burns associated with conductive keratoplasty. [J Refract Surg. 2016;32(11):776-778.].

Identification of Skin Electrical Injury Using Infrared Imaging: A Possible Complementary Tool for Histological Examination

In forensic practice, determination of electrocution as a cause of death usually depends on the conventional histological examination of electrical mark in the body skin, but the limitation of this method includes subjective bias by different forensic pathologists, especially for identifying suspicious electrical mark. The aim of our work is to introduce Fourier transform infrared (FTIR) spectroscopy in combination with chemometrics as a complementary tool for providing an relatively objective diagnosis. The results of principle component analysis (PCA) showed that there were significant differences of protein structural profile between electrical mark and normal skin in terms of α-helix, antiparallel β-sheet and β-sheet content. Then a partial least square (PLS) model was established based on this spectral dataset and used to discriminate electrical mark from normal skin areas in independent tissue sections as revealed by color-coded digital maps, making the visualization of electrical injury more intuitively. Our pilot study demonstrates the potential of FTIR spectroscopy as a complementary tool for diagnosis of electrical mark.

A Closer Look at the Thresholds of Thermal Damage: Workshop Report by an ICNIRP Task Group

The International Commission on Non-Ionizing Radiation Protection issued guidelines in 1998 for limiting public and occupational exposure to radiofrequency electromagnetic fields (100 kHz to 300 GHz). As part of the process of updating this advice, a 2-d workshop titled "A closer look at the thresholds of thermal damage" was held from 26-28 May 2015 in Istanbul to re-examine the thermal basis of the guidelines and to provide further information on heat-related effects and thresholds of thermal damage. Overall, the workshop provided much useful information relevant to revision of the guidelines. Participants indicated that the effects of heating from radiofrequency fields are consistent with those from other sources, and that the information derived from those studies can be applied to radiofrequency-induced heating. Another conclusion was that absolute temperature of tissues was more important for thermal damage than temperature change. The discussion suggested that the 6-min averaging time used in international guidelines was valid for whole-body exposures but with a large uncertainty: 30 min may be a more appropriate averaging time for localized exposures, and less than 1 min for implanted medical devices. The duration of whole-body radiofrequency exposure is a critical parameter that often determines the effect threshold, but this will be affected by other, ongoing thermoregulation, which is dependant on many factors. The thresholds for localized radiofrequency exposure were difficult to determine because of the potential range of exposure conditions and the possibility of radiofrequency-induced local hotspots. Suggestions for future dose metrics and further research were discussed and are included in this report.

Does Increased Electrocautery during Adenoidectomy Lead to Neck Pain?

OBJECTIVES: The objective was to assess the impact of electrocautery on complications in adenoidectomy. We sought to quantify cautery-related temperature changes in prevertebral fascia that may occur during the procedure, retrospectively evaluate the incidence of cautery-related complications, and prospectively assess the role of cautery in postoperative neck pain.

METHODS: Three consecutive related trials were performed. Initially, adenoidectomy was performed on 20 fresh cadavers, using a thermister to evaluate temperature changes in the prevertebral fascia after electrocautery (30 watts over a 30-second period). Next, retrospective analysis of adenoidectomy complications in 1206 children over a 5-year period was performed. Based on these findings, a prospective study of the incidence of neck pain following adenoidectomy was performed in a cohort of 276 children. Adenoidectomy technique, wattage, and duration of electro-cautery were recorded for each child. Children with significant neck pain were evaluated with MRI.

RESULTS: Peak thermister readings averaged 74°C, for a mean change of 51.8°C. Complications observed in retrospective analysis included neck pain (3), Grisel's syndrome (1), prolonged velopharyngeal insufficiency (1), retropharyngeal edema (1), and severe nasopharyngeal stenosis (1). The incidence of neck pain in the prospective study was 12% (33 pts), and was independent of adenoidectomy technique, cautery wattage, or duration of cautery use. MRIs revealed edema without abscess.

CONCLUSIONS: Cautery can result in substantial temperature changes in the surgical adenoid bed. Despite this, the incidence of complications, specifically neck pain, associated with adenoidectomy is low, although underreported. Complications appear to be independent of adenoidectomy technique and cautery use.

Humeral Neck Fracture after Electrocution - Case Report and Literature Review

A case of left humeral neck fracture following electrocution is reported in a 56-year old man, associated with partial thickness burns on his left hand. A fracture after accidental electrical shock injury represents a very unusual situation, due to muscle contractions. Surgeons involved in the management of the electrocuted patients should be aware of the possibility of musculoskeletal injuries. Neglecting these injuries can lead to delay in diagnosis and to detrimental complications.

Deep gluteal grounding pad burn after abdominal aortic aneurysm repair

Although skin burns at the site of grounding pad are a known risk of surgery, their exact incidence is unknown. We first report the case of a patient who presented a deep gluteal burn at the site of the grounding pad after an abdominal aortic aneurism repair, the etiology and the challenging treatment required to overcome this complication.

Offline impedance measurements for detection and mitigation of dangerous implant interactions: an RF safety prescreen

PURPOSE

The concept of a "radiofrequency safety prescreen" is investigated, wherein dangerous interactions between radiofrequency fields used in MRI, and conductive implants in patients are detected through impedance changes in the radiofrequency coil.

THEORY

The behavior of coupled oscillators is reviewed, and the resulting, observable impedance changes are discussed.

METHODS

A birdcage coil is loaded with a static head phantom and a wire phantom with a wire close to its resonant length, the shape, position, and orientation of which can be changed. Interactions are probed with a current sensor and network analyzer.

RESULTS

Impedance spectra show dramatic, unmistakable splitting in cases of strong coupling, and strong correlation is observed between induced current and scattering parameters.

CONCLUSIONS

The feasibility of a new, low-power prescreening technique has been demonstrated in a simple phantom experiment, which can unambiguously detect resonant interactions between an implanted wire and an imaging coil. A new technique has also been presented which can detect parallel transmit null modes for the wire.

Pathognomonic symptom associated with lightning strike: Lichtenberg figure

Lightning strikes especially occur during spring and summer months in the afternoons when there is heavy rain. In deaths resulting from lightning strike, there may either be no evidence on the dead person's clothes or body, or there may be burnt or torn patches on their clothes and lichtenberg figures specific to lightning strikes on their bodies. In such cases that also have a comorbid of cognitive dysfunction, since there is generally amnesia, having these figures during the physical examination has a valuable place in early diagnosis and quick treatment. This paper presents a case of lightning strike that was found to have Lichtenberg figures on the back and right leg after secondary examination.

Biomedical electrosurgery devices containing nanostructure for minimally invasive surgery: reduction of thermal injury and acceleration of wound healing for liver cancer

The aim of the present study was to investigate the thermal injury in the liver after a minimally invasive electrosurgery technique with a copper-doped diamond-like carbon (DLC-Cu) surface coating. To effectively utilize electrosurgery in a clinical caner setting, it is necessary to suppress the thermal injury to adjacent tissues. The surface morphologies of DLC-Cu thin films were characterized using scanning electron microscopy and transmission electron microscopy. Three-dimensional liver models were reconstructed using magnetic resonance imaging to simulate the electrosurgical procedure. Our results indicated that the temperature decreased significantly when minimally electrosurgery with nanostructured DLC-Cu thin films was used, and that it continued to decrease with increasing film thickness. In an animal model, thermography revealed that the surgical temperature was significantly lower in the minimally invasive electrosurgery with DLC-Cu thin film (DLC-Cu-SS) compared to untreated electrosurgery. In addition, DLC-Cu-SS created a relatively small thermal injury area and lateral thermal effect. These results indicated that the biomedical nanostructure coating reduced excessive thermal injury, and uniformly distributed temperature in the liver.

Taser and Conducted Energy Weapons

It is clear that CEWs are an increasingly prevalent law enforcement tool, adopted to address a complex and challenging problem. The potential for serious injury from a single deployment of a CEW is extremely low. The debate regarding the link between these electrical weapons and sudden in-custody death is likely to continue because their use is often in complex and volatile situations. Any consideration of injuries has to be put into that context. One must also consider what injuries to a subject would result if an alternative force method was used. Furthermore, the potential benefits of CEWs, including reduction in injuries to the public and law-enforcement officers, need to be considered.

[Forensic-medical diagnostics of an electrical mark resulting from the injury inflicted by technical electricity in the aqueous environment]

The objective of the present study was to develop the criteria for forensic-medical diagnostics of an electrical injury inflicted in the aqueous environment based on the characteristics of the electrical mark. The specific morphological features of the electrical injuries inflicted in the aqueous environment that were discovered in the materials available for the forensic medical expertise were analysed taking into consideration the results of the relevant research reported in the forensic medical literature. It was shown that an electrical injury inflicted in the aqueous environment results in the formation of an unusual mark in the form of blisters containing no watery liquid associated with electrogenic oedema in the surrounding tissues. Macroscopic and microscopic studies of the electrical mark failed to reveal the signs of grade III and IV grade thermal burning or thermally affected hair. It is concluded that the consistent characteristics of the electrical mark resulting from the injury inflicted by technical electricity in the aqueous environment include cell lengthening, blister formation inside the corneal layer, and the separation of epidermis from the skin proper.

[Burn injuries during MR scanning: a case report]

In this paper we report one case of skin burns in MRI caused by induced electrical currents. Two second degree skin burns occurred during imaging, while operating within all current safety guidelines. The currents are induced by the magnetic-gradient field, as well as the radiofrequency pulses. A closed conducting loop can occur while there is skin-to-skin contact, or for example when the patient is wearing ECG leads, monitoring sensors or cables. When a loop originates within the patient for a longer time, the current can resonate and dissipate high local energy through a rise in temperature. While rare, clinicians need to be aware of this possible event. By avoiding focal skin-to-skin contact of the extremities in this case, the adverse event could have been avoided.

Electrical burns in our workplace

BACKGROUND

There were totally 2320 patients during the period 2004-2013 hospitalised in our workplace with thermal injury, 87 of which were electric burns (3.75%).

RESULTS

The majority of electric burns occurred to men 67 cases (76.74%), then to children - 18 cases (20.94%) and the rest to women - 2 cases (2.32%). The mechanism of injury to the group of men was direct contact with the source of current (54.5%), electric arc injury (37.9%), ignition of clothes and subsequently flame (6.1%), and lightning injury (1.5%). The cause of injury to the group of children was contact injury (83.4%), electric arc injury (16.6%); no ignition or lightning injury occurred. The cause of injury in the group of women (2 cases) was contact injury for both; no arc, ignition or lighting injury occurred. The average extent of burn wounds was 11.7% in the group of men, 5.83% in the group of children and 2% in the group of women. Surgical treatment (necrectomy, skin grafting, flap, and amputation) was necessary in 41 cases in the group of men, in 15 cases in the group of children and in 2 cases in the group of women.

DISCUSSION AND CONCLUSION

Electric injury is a common problem in modern world. Some authors reported a 16.9% contribution of electric injuries of all hospitalised burn patients. There were 3.75% electric injury cases of all hospitalised burn patients in our department in the last nine years. The occurrence varies from year to year.

Endovascular catheter for magnetic navigation under MR imaging guidance: evaluation of safety in vivo at 1.5T

BACKGROUND AND PURPOSE

Endovascular navigation under MR imaging guidance can be facilitated by a catheter with steerable microcoils on the tip. Not only do microcoils create visible artifacts allowing catheter tracking, but also they create a small magnetic moment permitting remote-controlled catheter tip deflection. A side product of catheter tip electrical currents, however, is the heat that might damage blood vessels. We sought to determine the upper boundary of electrical currents safely usable at 1.5T in a coil-tipped microcatheter system.

MATERIALS AND METHODS

Alumina tubes with solenoid copper coils were attached to neurovascular microcatheters with heat shrink-wrap. Catheters were tested in carotid arteries of 8 pigs. The catheters were advanced under x-ray fluoroscopy and MR imaging. Currents from 0 mA to 700 mA were applied to test heating and potential vascular damage. Postmortem histologic analysis was the primary endpoint.

RESULTS

Several heat-mitigation strategies demonstrated negligible vascular damage compared with control arteries. Coil currents ≤300 mA resulted in no damage (0/58 samples) compared with 9 (25%) of 36 samples for > 300-mA activations (P = .0001). Tip coil activation ≤1 minute and a proximal carotid guide catheter saline drip > 2 mL/minute also had a nonsignificantly lower likelihood of vascular damage. For catheter tip coil activations ≤300 mA for ≤1 minute in normal carotid flow, 0 of 43 samples had tissue damage.

CONCLUSIONS

Activations of copper coils at the tip of microcatheters at low currents in 1.5T MR scanners can be achieved without significant damage to blood vessel walls in a controlled experimental setting. Further optimization of catheter design and procedure protocols is necessary for safe remote control magnetic catheter guidance.

Electrothermal ring burn from a car battery

Despite prevention efforts, burn injuries among auto mechanics are described in the literature. Electrothermal ring burns from car batteries occur by short-circuiting through the ring when it touches the open terminal or metal housing. This article describes a 34-year-old male auto mechanic who was holding a wrench when his gold ring touched the positive terminal of a 12-volt car battery and the wrench touched both his ring and the negative terminal. He felt instant pain and had a deep partial-thickness circumferential burn at the base of his ring finger. No other soft tissues were injured. He was initially managed conservatively, but after minimal healing at 3 weeks, he underwent a full-thickness skin graft. The graft incorporated well and healed by 4 weeks postoperatively. He had full range of motion. The cause of ring burns has been controversial, but based on reports similar to the current patient's mechanism, they are most likely electrothermal burns. Gold, a metal with high thermal conductivity, can heat up to its melting point in a matter of seconds. Many treatments have been described, including local wound care to split- and full-thickness skin grafts. Because most burns are preventable, staff should be warned and trained about the potential risks of contact burns. All jewelry should be removed, and the live battery terminal should be covered while working in the vicinity of the battery.

Invisible metallic microfiber in clothing presents unrecognized MRI risk for cutaneous burn

SUMMARY

We report a case of a thermal burn that occurred during MR imaging likely caused by invisible silver-embedded microfibers in the fabric of an undershirt. As the prevalence of fabric containing nondetectable metallic microfiber increases in athletic and "tech" clothing, the importance of having patients change into safe facility-provided garments before MR imaging is emphasized.

Clinical evaluation of a new technique to monitor return electrode skin temperature during radiofrequency ablation

PURPOSE

Return electrode burns occur occasionally in cardiac radiofrequency ablation and more frequently in tumor radiofrequency ablation. A return electrode incorporating a thermochromic liquid crystal (TLC) layer, which changes color with temperature, has been shown in sheep studies to accurately indicate underlying skin temperature. We aimed to validate the accuracy of TLC-coated return electrodes in indicating skin temperature in the clinical setting of cardiac radiofrequency ablation.

METHODS AND RESULTS

The top layer of a standard return electrode was replaced with TLC. Fluoro-optic thermometer (FOT) probes were laid on the skin side of the return electrode, which was then placed on the left lateral mid-thigh of 18 patients (mean age = 61 ± 12 years, 12 men) undergoing cardiac radiofrequency ablation. Return electrode photographs were taken when FOT temperature exceeded 35 °C. TLC color changes, observed in 11 patients, were converted to temperature and compared with FOT temperature. TLC temperature correlated well with FOT temperature (Pearson's coefficient = 0.97 ± 0.03). Bland-Altman analysis showed good agreement (mean temperature difference = -0.04 ± 0.08 °C, upper limit of agreement = 0.11 ± 0.005 °C, lower limit of agreement = -0.19 ± 0.005 °C). The maximum FOT temperature recorded was 39.6 °C. There was no thermal injury at the return electrode site on any patients, when assessed immediately after and the day following the procedure.

CONCLUSION

TLC-coated return electrodes accurately indicate underlying skin temperature in cardiac radiofrequency ablation and may help prevent burns. This technology might be essential in high energy radiofrequency ablation.

Sonographically guided radiofrequency ablation with and without a superficial saline injection to prevent skin burns in a rabbit model

OBJECTIVES

Our aim was to determine whether sonographically guided radiofrequency ablation with superficial saline injection can minimize thermal injury of the skin without an influence on therapeutic efficacy.

METHODS

Institutional Animal Care Committee approval was obtained. Twelve percutaneous radiofrequency ablation procedures were performed in the thighs of 6 rabbits (control, n = 6, right thigh; experimental, n = 6, left thigh). The ablation with local anesthesia was performed in the most superficial area of the thigh muscle. In the experimental group, 1 mL of saline was injected before the ablation at the tissue layer between the skin and ablated muscle. The duration and energy of the ablation were the same in the control and experimental groups. Rabbits were compared for their gross skin state and histopathologic findings after the ablation.

RESULTS

The degree of thermal coagulation of the muscle was similar in both groups at pathologic examination. Grossly, skin redness was mild in the experimental group but moderate in the control group. Of the 6 rabbits, 5 tended to show more frequent histopathologic changes, including an inflammatory reaction, interruption of collagen fibers, injury of the skin adnexa, and fibrosis, in the control group when compared with the experimental group. However, there was no statistically significant difference (all P> .05). One rabbit that underwent ablation at higher energy had a partially dissected epidermis in the control group only.

CONCLUSIONS

Sonographically guided radiofrequency ablation with a saline injection superficial to a tumor might prevent skin burns and provide equivalent therapeutic efficacy for ablating superficial lesions.

Reducing the risk of burns during electroconvulsive therapy

Poor contact between electroconvulsive therapy (ECT) electrodes and the skin can result in patient burns during ECT treatment. Proper site preparation and electrode application are essential to ensure adequate contact and to reduce the risk of burns.

Insulation failure in robotic and laparoscopic instrumentation: a prospective evaluation

OBJECTIVE

The purpose of this study was to detect the incidence, prevalence, and location of insulation failures (IFs) in laparoscopic and robotic instruments.

STUDY DESIGN

In phase A, a total of 78 robotic and 298 laparoscopic instruments were tested at 20 W and 2.64 kV at Mayo Clinic in Arizona. In phase B, 60 robotic and 308 laparoscopic instruments were tested at 20 W/1 kV and 20 W/4.2 kV, respectively.

RESULTS

In phase A, the robotic group showed a higher prevalence (25/78; 32%) and incidence of IFs after 10 uses (35/44 instruments; 80%) when compared with laparoscopy (prevalence, 39/298 [13%]; incidence, 68/189 [36%]; P<.05). In phase B, IFs were detected in 81.7% of the robotic instruments and in 19.5% of the laparoscopic instruments (P<.005).

CONCLUSION

There is a high incidence and prevalence of IF in endoscopic instrumentation that is more common in the robotic group.

Children with burn injuries--assessment of trauma, neglect, violence and abuse

Burns are an important cause of injury to young children, being the third most frequent cause of injury resulting in death behind motor vehicle accidents and drowning. Burn injuries account for the greatest length of stay of all hospital admissions for injuries and costs associated with care are substantial. The majority of burn injuries in children are scald injuries resulting from hot liquids, occurring most commonly in children aged 0-4 years. Other types of burns include electrical, chemical and intentional injury. Mechanisms of injury are often unique to children and involve exploratory behavior without the requisite comprehension of the dangers in their environment. Assessment of the burnt child includes airway, breathing and circulation stabilization, followed by assessment of the extent of the burn and head to toe examination. The standard rule of 9s for estimating total body surface area (TBSA) of the burn is inaccurate for the pediatric population and modifications include utilizing the Lund and Browder chart, or the child's palm to represent 1% TBSA. Further monitoring may include cardiac assessment, indwelling catheter insertion and evaluation of inhalation injury with or without intubation depending on the context of the injury. Risk factors and features of intentional injury should be known and sought and vital clues can be found in the history, physical examination and common patterns of presentation. Contemporary burn management is underscored by several decades of advancing medical and surgical care however, common to all injuries, it is in the area of prevention that the greatest potential to reduce the burden of these devastating occurrences exists.

RF Heating of MRI-Assisted Catheter Steering Coils for Interventional MRI

RATIONALE AND OBJECTIVES

The aim of this study was too assess magnetic resonance imaging (MRI) radiofrequency (RF)-related heating of conductive wire coils used in magnetically steerable endovascular catheters.

MATERIALS AND METHODS

A three-axis microcoil was fabricated onto a 1.8Fr catheter tip. In vitro testing was performed on a 1.5-T MRI system using an agarose gel-filled vessel phantom, a transmit-receive body RF coil, a steady-state free precession pulse sequence, and a fluoroptic thermometry system. Temperature was measured without simulated blood flow at varying distances from the magnet isocenter and at varying flip angles. Additional experiments were performed with laser-lithographed single-axis microcoil-tipped microcatheters in air and in a saline bath with varied grounding of the microcoil wires. Preliminary in vivo evaluation of RF heating was performed in pigs at 1.5 T with coil-tipped catheters in various positions in the common carotid arteries with steady-state free precession pulse sequence on and off and under physiologic-flow and zero-flow conditions.

RESULTS

In tissue-mimicking agarose gel, RF heating resulted in a maximal temperature increase of 0.35°C after 15 minutes of imaging, 15 cm from the magnet isocenter. For a single-axis microcoil, maximal temperature increases were 0.73°C to 1.91°C in air and 0.45°C to 0.55°C in saline. In vivo, delayed contrast-enhanced MRI revealed no evidence of vascular injury, and histopathologic sections from the common carotid arteries confirmed the lack of vascular damage.

CONCLUSIONS

Microcatheter tip microcoils for endovascular catheter steering in MRI experience minimal RF heating under the conditions tested. These data provide the basis for further in vivo testing of this promising technology for endovascular interventional MRI.

Energizing Richard Wolf E-Line stricture blades can result in electrosurgical burns

Stricture blades sold by Richard Wolf for use with its E-Line resectoscopes can be mistaken for electrodes and used for electrosurgical applications, potentially resulting in alternate-site electrosurgical burns. Users of these products--and similar products that may be marketed by other endoscopy suppliers--must be adequately trained on the proper identification and use of these instruments.

Hazard report. Reducing the risk of burns from surgical light sources

Surgical light sources can heat instruments enough to burn patients and can even start small fires in the operating room. Hospitals can reduce this risk by educating clinicians on the proper use of these devices and by purchasing models that incorporate certain safety features.

Avoiding oral burns during electrocautery tonsillectomy

Electrocautery tonsillectomy is a common method of tonsil removal, and electrocautery devices are widely available. Although these devices are relatively safe, inadvertent patient injury may occur with their use, such as oral cavity burns. We describe a simple surgical technique that reduces the risk of oral burns during electrocautery tonsillectomy and review additional safety considerations.

Development of an MR safe reach and grasp movement evaluation system to study brain activation patterns after stroke

An MR safe apparatus is important for the for monitoring of tasks in the magnetic resonance (MR) environment. This paper describes the development of an MR safe movement evaluation system to measure the hand grasp and elbow flexion/extension movements. The system will be used to monitor motor performance in the fMRI environment and assess functional and motor impairment level pre and post robot-assisted therapy.

Perineural air injection as a means of prevention of thermal injury of the sciatic nerve during radio frequency ablation: a preliminary experimental study in rabbits

OBJECTIVE

The purpose of this study was to determine whether perineural air injection before radio frequency (RF) ablation of thigh muscles can minimize thermal injury to the sciatic nerve.

METHODS

Eighteen percutaneous RF ablation procedures were performed in the thighs of 9 rabbits (control, n = 9, right thigh; experimental, n = 9, left thigh) with an internally cooled electrode (1-cm active tip). In the control group, the tip of the electrode was located in posterior muscles 5 mm away from the sciatic nerve before ablation. In the experimental group, sonographically guided air injection into the perineural space was performed just before ablation. Animals were killed 7 days after ablation, and the presence or absence of pathologic changes of the sciatic nerves (axonal necrosis, myelin digestion, endoneurial fibrosis, perineurial fibrosis, and dystrophic calcification) in both groups were compared under an optical microscope.

RESULTS

Perineural air injection was achieved successfully with a single puncture in all rabbits in the experimental group. All of the pathologic findings were observed much more frequently in the control group, and the differences in the frequencies of axonal necrosis and myelin digestion of the sciatic nerve between the groups were clinically significant (P < .05).

CONCLUSIONS

Perineural air injection may be useful for reducing the frequency of thermal injury during RF ablation of lesions adjacent to nerves.

Suction cautery and electrosurgical risks in otolaryngology

BACKGROUND

Flash fires, mucosal injuries and commissure burns during otolaryngology procedures have been largely attributed to anesthetic and surgical errors. Reports of direct electrosurgical device related events are rare. The discovery of thermal damage to the oral commissure during routine suction cautery adenoidectomy at our institution prompted a detailed investigation of the device's thermal properties. We complement this analysis with a review of electrocautery device related injuries reported in otolaryngology literature.

METHODS

FLIR Systems Thermovision A40 infrared camera was used to evaluate temperature changes along the electrosurgical wand of suction cautery devices. Shaft temperatures were measured at specific times of continuous use, distances along the shaft, and cautery settings. A literature search of electrocautery-associated injuries during upper aerodigestive procedure was then performed. Nine pediatric otolaryngologists were then interviewed for historical experience with electrocautery injuries.

RESULTS

Temperatures exceeding 60 degrees C, and sufficient to cause thermal soft tissue damage, occurred along the suction cautery wand at a setting of 40 Watts (W). These temperatures traveled far enough to appose the oral commissure when the device was simultaneously in continuous use, in the fulgurate mode, and with the suction turned off. Literature review identified eleven articles specifically pertaining to electrosurgical injuries during routine oropharyngeal procedures. Flash fires and their associated burns were the most frequently reported complication. Conversely, seven of ten cases elicited from peer interviews were oral or commissure burns attributed to improper insulation of electrocautery devices.

CONCLUSIONS

Inadvertent electrosurgical injuries during routine otolaryngology procedures can result from inadequate equipment insulation. Techniques to reduce the likelihood of these events are discussed.

Fire/burn risk with electrosurgical devices and endoscopy fiberoptic cables

PURPOSE

The purpose of the study was to systematically explore the fire and burn risk associated with fiberoptic cables and electrosurgical devices.

MATERIALS AND METHODS

A 300-W light source was connected to a standard gray fiberoptic light cable. The end of the cable was either rested atop or buried within a cotton towel or polypropylene drape in the presence or absence of 100% oxygen for up to 10 minutes. A monopolar electrosurgical device set at 1 W, 10 W, or 30 W was tested on a cotton towel or polypropylene drape for a period of 30 seconds. All trials were repeated.

RESULTS

Resting the light cable on top of the cotton towel or polypropylene drape with or without oxygen produced no result. Burying the end of the cable within the drape produced a hole in the drape within 15 seconds both with and without oxygen. Burying the end of the cable within the cotton towel produced a yellow discoloration after 2 minutes both with and without oxygen. The monopolar electrosurgical device set at 30 W burned immediately through the polypropylene drape, producing a skin burn. All other trials with monopolar electrocautery produced no result. No flame or fire was produced in any trial.

CONCLUSIONS

Fiberoptic cables and electrosurgical generators represent a serious burn risk for surgical patients, with operating room drapes and towels affording only limited protection. Otolaryngologists should be keenly aware of the risks that these devices represent because our specialty uses them frequently.

Beyond the basics: lightning-strike injuries

It is estimated that a lightning flash occurs approximately 8 million times per day throughout the world. Most strikes are benign and cause little damage to property and physical structures; however, when lightning strikes a person or group of people, it is a significant medical and potentially traumatic event that could lead to immediate death or permanent disability. By understanding some basic physics of lightning and pathophysiology of injuries associated with lightning strikes, EMS providers will be better prepared to identify assessment findings, anticipate complications and provide effective emergency care.