Earticle

본 연구는 경남 남해군 독일마을 전원주택 화목보일러연통에서 발생한 화재를 중심으로 연구하였다. 이 화재는 전원주택을 건축할 때 미관상 선호도가 높고, 낭만을 추구하고자 설치한 “화목난로” 즉 화목보일러 연통과 인접한 지붕에서 시작된 화재로, 에너지손실 최소화를 위한 건축자재인 인슐레 이션(유리원석을 1000℃ 부근에서 용융시켜 섬유 화 한 것임), 석고보드 등 내화재, 단열재를 활용한 건축과정에서 발생하였다. 이러한 화재사례를 바탕으로 화재원인을 분석하고, 재현실험을 통해 보편적 으로 안전하다고 생각되는, 단열재 및 내화재료와 발화가능성과의 상간관계를 문헌고찰 및 다각적인 재현실험을 통해 화재로 부터 안전할 수 있는지 검토하였으며, 화목보일러 연통의 제작방식에 따른 문 제점을 분석, 건축기술 및 재료의 안전한 기준이 무엇인지 방향성을 제시하고, 화재예방을 위한 제도 적 보완점을 점검해 본다. 아울러 이와 관련된 화재발생 관계자(설비업체, 주택소유자)간의 법적분쟁사례를 통해 보험법, 하자 담보책임법, 소방법등이 적용되는 현주소(범위)를 되짚어보고, 안전한국의 구축을 위한 정보를 공유하고자 한다.

Objective: To comprehensively assess the relationship between nerve conduction study (NCS), sympathetic skin response (SSR), and demographic factors in patients with diabetic neuropathy, exploring potential risk factors and mechanisms.Methods: A retrospective study (N=184) included patients diagnosed with type 2 diabetes mellitus undergoing NCS and SSR. Demographic, clinical, and laboratory data were analyzed. Patients were categorized by diabetic peripheral neuropathy (DPN) and SSR stages for comparative analysis.Results: HbA1c levels correlated with DPN progression. SSR stages exhibited age-related differences. Height correlated with DPN but not SSR stages. Body mass index showed no significant differences.Conclusion: While DPN progression correlated with glycemic control and duration of diabetes, SSR was influenced by age. Unexpectedly, cholesterol levels remained within the normal range, challenging established concepts. Understanding these relationships is crucial for interpreting test results and developing targeted interventions for diabetic neuropathy.

Thenar motor neuropathy is a rare, pure motor neuropathy of the median nerve with delayed motor latency in electrophysiological studies. We present an extremely rare case of idiopathic thenar motor neuropathy with complete median motor conduction block at the carpal tunnel level, which was confirmed by ultrasonographic and surgical findings. Right median nerve conduction studies demonstrated normal sensory responses and no motor response in the abductor pollicis brevis (APB). Needle electromyography of the right APB showed no recruitment of motor unit action potentials. Ultrasonographic examination demonstrated enlarged and swollen median nerve fascicles within the carpal tunnel. A carpal tunnel release operation was performed; the median nerve underneath the transverse carpal ligament was swollen and blanched due to decreased vascularity, suggesting the presence of compression. Pain in the thenar area improved 2 weeks after surgery. Herein, we emphasize the usefulness of ultrasonographic evaluations in determining the level of the nerve injury in cases with doubtful electrophysiological results.

Objective To evaluate each digital branch of the median sensory nerve and motor nerves to abductor pollicis brevis (APB) and 2nd lumbrical (2L) according to the severity of carpal tunnel syndrome (CTS).Methods A prospective study was performed in 67 hands of 41 patients with CTS consisting of mild, 23; moderate, 27; and severe cases, 17. Compound muscle action potentials (CMAPs) were obtained from APB and 2L, and median sensory nerve action potentials (SNAPs) were recorded from the thumb to the 4th digit. Parameters analyzed were latency of the median CMAP, latency difference of 2L and first palmar interosseous (PI), as well as latency and baseline to peak amplitude of the median SNAPs.Results The onset and peak latencies of the median SNAPs revealed significant differences only in the 2nd digit, according to the severity of CTS, and abnormal rates of the latencies were significantly lower in the 2nd digit to a mild degree. The amplitude of SNAP and sensory nerve conduction velocities were more preserved in the 2nd digit in mild CTS and more affected in the 4th digit in severe CTS. CMAPs were not evoked with APB recording in 4 patients with severe CTS, but obtained in all patients with 2L recording. 2L-PI showed statistical significance according to the severity of CTS.Conclusion The branch to the 4th digit was mostly involved and the branch to the 2nd digit and 2L were less affected in the progress of CTS. The second digit recorded SNAPs and 2L recorded CMAPs would be valuable in the evaluation of severe CTS.

Objective To perform nerve conduction studies of the four branches of the superficial peroneal nerves to determine normal values and anatomic variations in Koreans. Method Antidromic sensory nerve conduction studies of the four distal branches were performed on 70 healthy subjects (100 feet). We applied electrical stimulation at the midpoint of medial and lateral malleoli for the medial dorsal cutaneous nerve (MDCN), and at the lateral 1/4 point between the medial and lateral malleoli for the 2 branches of the intermediate dorsal cutaneous nerve (IDCN). Results Reference values (mean±SD) of the onset/ peak latency (ms)/ sensory action potential amplitude (μV) for the two branches of the MDCN and for the first branch of the IDCN were 2.2±0.3/2.9±0.3/9.2±3.1, 2.2±0.3/2.8±0.3/9.1±3.0 and 2.3±0.4/2.9±0.3/8.5±2.8, respectively. For the second IDCN branch, the reference values were 2.3±0.4/3.0±0.4/7.1±2.6 but anomalous sural innervation was also found. Three types of IDCN innervations to the fourth interdigital web space were detected. In type I, the fourth interdigital webspace was innervated solely by the IDCN, whereas in type II, it was innervated by both the IDCN and distal sural nerve. In type III, it was solely innervated by the distal sural nerve. Conclusion The results of this study show the reference values of the distal sensory branches of the superficial peroneal nerve, and provide information on the variant innervations to the fourth interdigital web space.

Objective To derive normative values for ulnar nerve conduction study of the active recording electrode on the fi rst dorsal interosseous muscle (FDI) and the reference electrode on the proximal phalanx of the thumb. Method Ulnar nerve motor conduction study with FDI and abductor digiti minimi muscle (ADM) recording was performed in 214 hands of 107 healthy subjects. Ulnar NCS was performed with 2 different recording electrode montages (ADM-base of 5th finger; FDI-thumb) and diff erences in latency and amplitude were compared. Using this technique, the initial positivity of ulnar compound muscle action potential (CMAP) was not observed in any response with FDI recording. Results The maximal values for distal motor latency to the ADM and FDI muscle were 3.8 ms and 4.4 ms,respectively. Th e maximal difference of distal motor latency between the bilateral FDI recordings was 0.6 ms. The maximal ipsilateral latency difference between ADM and FDI was 1.4 ms. Conclusion Placement of the reference electrode on the thumb results in a CMAP without an initial positivity and the normative values obtained may be useful in the diagnosis of ulnar neuropathy at the wrist.

Objective To develop a set of reference standards for tibial motor, common peroneal motor, sural sensory, and superficial peroneal sensory nerve conduction studies (NCSs) with expanded uncertainty in a healthy Korean population.Methods Standardized procedures were conducted for individual lower extremity NCSs of 199 healthy participants in their 20s (n=100) and 50s (n=99). Mean values and expanded uncertainties for parameters were analyzed with thorough consideration of multiple uncertainty factors under the International Guide to the Expression of Uncertainty in Measurement. In addition, side-to-side differences in onset latency, amplitude, and nerve conduction velocity (NCV) were analyzed.Results Mean (reference range) for distal onset latency, baseline to negative peak amplitude, NCV of tibial motor nerve in males in their 20s were 4.3 ms (3.1?5.4 ms), 7.1 mV (3.4?10.9 mV), and 50.7 m/s (42.2?59.3 m/s), respectively; sural sensory nerve baseline to negative peak amplitude in males in their 20s was 21.7 μV (8.3?35.2 μV). Including the aforementioned data, we present a vast dataset of normative mean values and expanded uncertainties for NCSs of the leg in a healthy Korean population. Furthermore, upper limits for normal side-to-side differences for onset latency, amplitude, and NCV of each nerve are suggested.Conclusion To our knowledge, this is the first study to present the reference standards of leg NCSs with consideration for multifactorial uncertainties in an Asian population. We expect these results to help practitioners make reliable and reproducible clinical decisions.

Objective To obtain reference values, to suggest optimal recording and stimulation site for radial motor nerve conduction study (RmNCS), and to analyze the correlation among RmNCS parameters, demographics and ultrasonography (US) findings.Methods A total of 55 volunteers participated in this study. We hypothesized that ‘lateral edge of spiral groove (A)’ was the optimal stimulation site, and the ‘largest cross-sectional area (CSA) of extensor indicis proprius (EIP) muscle (B)’ was the optimal recording site. The surface distance between ‘A’ and the lateral epicondyle of the humerus divided by upper arm length, was named the spiral groove ratio. The surface distance between ‘B’ and the ulnar styloid process divided by forearm length, was named the EIP ratio. Using US, we identified these sites, and further conducted RmNCS.Results Data was collected from 100 arms of the 55 volunteers. Mean amplitude and latency were 5.7±1.1 mV and 5.7±0.5 ms, respectively, at the spiral groove, and velocity between elbow and spiral groove was 73.7±7.0 m/s. RmNCS parameters correlated significantly with height, weight, arm length, and CSA of the EIP muscle. Spiral groove ratio and EIP ratio were 0.338±0.03 and 0.201±0.03, respectively; both values were almost the same, regardless of age, sex and handedness.Conclusion We established a reference value and standardized method of RmNCS using US. Optimal RmNCS can be conducted by placing the recording electrode 20% (about one-fifth) of forearm length from the ulnar styloid process, and stimulating at 34% (about one-third) of the humeral length from the lateral epicondyle.

Extended Graetz problem in microtube is analyzed by using eigenfunction expansion to solve the energy equation. For the eigenvalue problem we applied the shooting method and Galerkin method. The hydrodynamically isothermal developed flow is assumed to enter the microtube with uniform temperature or uniform heat flux boundary condition. The effects of velocity and temperature jump boundary condition on the microtube wall, axial conduction and viscous dissipation are included. From the temperature field obtained, the local Nusselt number distributions on the tube wall are obtained as the dimensionless parameters (Peclet number, Knudsen number, Brinkman number) vary. The fully developed Nusselt number for each boundary condition is obtained also in terms of these parameters.

Objective: To establish the reference standard of the median nerve conduction study (NCS) in Korea.Methods: A total of 648 median motor and 602 median sensory NCSs from 349 Korean healthy volunteers were tested and analyzed prospectively. Equipment calibration, assessment of intraand inter-rater reliability, and the NCSs per se were conducted according to a predetermined protocol. A reference standard was established from uncertainty components for the following parameters: the onset and peak latencies; the baseline-to-peak and peak-to-peak amplitudes; the area and duration of the negative wave; and the nerve conduction velocity. The effects of sex, age and stimulation intensity were analyzed.Results: Each measured value of 648 median motor and 602 median sensory nerves were obtained and presented with both mean and expanded uncertainties, as well as mean and standard deviations. The cut-off values with expanded uncertainty were determined for different age and sex groups. After adjusting for anthropometric covariates, all parameters except duration were affected by age, and sex appeared to influence both duration and area. While stimulation intensity significantly affected some parameters including latencies, the effect sizes were negligible.Conclusion: We propose the median NCS reference standard using the largest Korean dataset ever available. The use of the traceable and reliable reference standard is anticipated to promote more accurate and dependable diagnosis and appropriate management of median neuropathies in Korea.

Objective To establish a supraorbital nerve sensory conduction recording method and assess its usefulness. Methods Thirty-one healthy subjects without a history of trauma or neurological disease were recruited. For the orthodromic procedure, the recording electrode was attached immediately superior to the supraorbital notch. The stimulation electrode was placed on points along the hairline which evoked the largest sensory nerve action potentials (SNAPs). The antidromic sensory response was recorded after switching the recording and stimulating electrodes. The measured parameters were onset latency, peak latency, and baseline to peak amplitude of the SNAPs. The electrophysiological parameters of the bilateral supraorbital nerves were compared. We also recruited two patients who had sensory deficits on one side of their foreheads because of laceration injuries. Results The parameters of orthodromically recorded SNAPs were as follows: onset latency 1.21±0.22 ms (range, 0.9?1.6 ms), peak latency 1.54±0.23 ms (range, 1.2?2.2 ms), and baseline to peak amplitude 4.16±1.92 ?V (range, 1.4?10 ?V). Those of antidromically recorded SNAPs were onset latency 1.31±0.27 ms (range, 0.8?1.7 ms), peak latency 1.62±0.29 ms (range, 1.3?2.2 ms), and baseline to peak amplitude 4.00±1.89 ?V (range, 1.5?9.0 ?V). There was no statistical difference in onset latency, peak latency, or baseline to peak amplitude between the responses obtained using the orthodromic and antidromic methods, and the parameters also revealed no statistical difference between the supraorbital nerves on both sides. Conclusion We have successfully recorded supraorbital SNAPs. This conduction technique could be quite useful in evaluating patients with supraorbital nerve lesions.

The human body and nervous system transmit information through electric charges. After the electric charge transmits information to the brain, we can feel pain, numbness, comfort, and other feelings. Electric therapy is currently used widely in clinical practice because the field of examination is more representative of electrocardiogram, and in the field of treatment is more representative of electrotherapy. In this study, we design a system for neurophysiological therapy and conduct parameter calculation and model selection for the components of the system. The system is based on a discontinuous conduction mode (DCM) boost circuit, and controlled and regulated by a single-chip microcomputer. The system does not only have a low cost but also fully considers the safety of use, convenience of the human-computer interface, adjustment sensitivity, and waveform diversity in the design. In future, it will have strong implications in the field of electrotherapy.

Objective To verify the utility of the lateral femoral cutaneous nerve (LFCN) ultrasound-guided conduction technique compared to that of the conventional nerve conduction technique.Methods Fifty-eight legs of 29 healthy participants (18 males and 11 females; mean age, 42.7±14.9 years) were recruited. The conventional technique was performed bilaterally. The LFCN was localized by ultrasound. Cross-sectional area (CSA) of the LFCN and the distance between the anterior superior iliac spine (ASIS) and the LFCN was measured. The nerve conduction study was repeated with the corrected cathode location. Sensory nerve action potential (SNAP) amplitudes of the LFCN were recorded and compared between the ultrasound-guided and conventional techniques. Results Mean body mass index of the participants was 23.7±3.5 kg/m2, CSA was 4.2±1.9 mm2, and the distance between the ASIS and LFCN was 5.6±1.7 mm. The mean amplitude values were 6.07±0.52 μV and 6.66±0.54 μV using the conventional and ultrasound-guided techniques, respectively. The SNAP amplitude of the LFCN using the ultrasound-guided technique was significantly larger than that recorded using the conventional technique. Conclusion Correcting the stimulation position using the ultrasound-guided technique helped obtain increased SNAP amplitude.

Objective To understand various morphologic types and locations of the sural nerve (SN) that are important for nerve conduction studies or nerve grafting procedures. The aim of this study was to describe the course and variations of the SN based on ultrasonographic findings for an adequate nerve conduction study.Methods A total of 112 SNs in 56 volunteers with no history of trauma or surgery were examined by ultra-sonography. The location and formation of the SNs in relation to the medial and lateral sural cutaneous nerve were investigated. We measured the horizontal distance between the SNs and the midline of the calf at the level of 14 cm from the lateral malleolus, and the distance between the SNs and the most prominent part of the lateral malleolus. Results SN variants was classified into four types according to the medial and lateral sural cutaneous nerve; type 1 (73.2%), type 2 (17.9%), type 3 (8.0%), and type 4 (0.9%). The mean distance between the SN and the midline of the calf was 1.02±0.63 cm, the SN and the most prominent part of the lateral malleolus was 2.14±0.15 cm.Conclusion Variations in the location and formation of the SN was examined by ultrasonography, and the results of this study would increase the accuracy of the SN conduction study.

Objective To understand the neural generator of double-peak potentials and the change of latency and amplitude of double peaks with aging. Method In 50 healthy subjects made up of groups of 10 people per decade from the age of 20 to 60, orthodromic sensory nerve conduction studies were performed on the median nerves using submaximal stimulation. Various stimulus durations and interstimulation distances were used to obtain each double peak in the different age groups. The latency and amplitude of the second peak were measured. Statistical analyses included one-way ANOVA and correlation tests. p-values<0.05 were considered significant. Results When the cathode moved in a proximal direction, the interpeak intervals increased. Second peak amplitudes decreased, and second peak latencies were delayed with aging (p<0.05). In some older people, second peaks were not obtained. Conclusion Our experiments indicate that the double-peak response represented the two stimulation sites under the cathode and anode. The delayed latency and decreased amplitude of the second peak that occurs with aging represented peripheral nerve degeneration in aging, which starts at the distal nerve.

Objective To determine the optimal stimulation and recording site for infrapatellar branch of saphenous nerve (IPBSN) conduction studies by a cadaveric study, and to confirm that obtained location is practically applicable to healthy adults. Methods Twelve lower limbs from six cadavers were studied. We defined the optimal stimulation site as the point IPBSN exits the sartorius muscle and the distance or ratio were measured on the X- and Y-axis based on the line connecting the medial and lateral poles of the patella. We defined the optimal recording site as the point where the terminal branch met the line connecting inferior pole of patella and tibial tuberosity, and measured the distance from the inferior pole. Also, nerve conduction studies were performed with obtained location in healthy adults. Results In optimal stimulation site, the mean value of X-coordinate was 55.50±6.10 mm, and the ratio of the Y-coordinate to the thigh length was 25.53%±5.40%. The optimal recording site was located 15.92±1.83 mm below the inferior pole of patella. In our sensory nerve conduction studies through this location, mean peak latency was 4.11±0.30 ms and mean amplitude was 4.16±1.49 mV. Conclusion The optimal stimulation site was located 5.0?6.0 cm medial to medial pole of the patella and 25% of thigh length proximal to the X-axis. The optimal recording site was located 1.5?2.0 cm below inferior pole of patella. We have also confirmed that this location is clinically applicable.

Objective: To investigate the relationship between the absent rates of superficial peroneal sensory nerve action potential (SNAP) and age increase in healthy adults without symptoms of peripheral neuropathy. Method: We recruited 120 healthy adults (240 low extremities) and divided into the age groups 20~29, 30~39, 40~49, 50~59, 60~69 and more than 70 years. All subjects underwent sensory nerve conduction study of superficial peroneal nerve. Diabetic history, exposed to neurotoxic agent, neurologic problem, trauma history on low extremity and pitting edema were excluded in this study. Results: All subjects of age groups 20~29, 30~39, 40~49 and 50~59 years were elicited, but 2 subjects (1.7%) in age group 60~69 years and 7 subjects (5.8%) in age group more than 70 years were not elicited. Increasing age and the no response rate of superficial peroneal nerve conduction study were correlated statically significant (p-value = 0.004). Using a receiver operator characteristic (ROC) curve, absent superficial peroneal SNAP could be observed more than 70.5 years with sensitivity of 77.8% and specificity of 89.2%. Conclusion: The ratio of absent superficial peroneal SNAP can be increase in elderly healthy adults. This study shows reference that superficial peroneal SNAP might be absent as age increase.