Injury Failure Research Articles

Risk Factors for Injury During Typhoon Saomei

Little is known about risk factors for typhoon-related injury. On 10 August 2006, Typhoon Saomei (one of the strongest typhoons on record) struck Southern China. We conducted a census in Longhua Village, Fujian Province to assess typhoon-related injury, and carried out a matched case-control analysis to evaluate risk factors. Of the 3002 residents interviewed, 136 (4.5%) were injured, and 7 were reported by family members to have died (2.3 per 1000). Injuries were highest with the first peak of wind speed. Living in houses directly facing the sea, compared with living in the last row of houses, was associated with an increased risk (relative risk = 18 [95% confidence interval (CI) = 5.7-55]). Important risk factors were failure to reinforce doors or windows (adjusted odds ratio = 13 [95% CI = 2.4-76]), staying in a damaged room (8.7 [2.5-31]), and staying near a window or door (12 [4.1-38]). Injuries with typhoon Saomei were related to both wind speed and failure to take specific preventive measures.

Metalloproteinase Expression is Associated with Traumatic Wound Failure

Matrix metalloproteinases (MMPs) are crucial in the inflammatory and remodeling phases of wound healing. We previously reported the correlation between pro-inflammatory cytokines and timing of successful combat-wound closure. We now extend our studies to investigate the correlation between wound-remodeling MMP expression and wound healing. Thirty-eight wounds in 25 patients with traumatic extremity combat wounds were prospectively studied. Surgical debridement with vacuum-assisted closure (VAC) device application was repeated every 48 to 72h until surgical wound closure. Wound effluent and patient serum were collected at each wound debridement and analyzed for five matrix metalloproteinases using the Luminex multiplex system; Millipore Corp, Billerica, MA. The primary outcome was wound healing within 30 d of definitive wound closure. Impairment was defined as delayed wound closure (>21 d from injury) or wound dehiscence. MMP expression was compared between impaired and normal healing wounds. Elevated levels of serum MMP-2 and MMP-7 and reduced levels of effluent MMP3 were seen in impaired wounds (n = 9) compared with wounds that healed (n = 29; P<0.001). Receiver operating characteristic (ROC) curve analysis yielded area-under-the-curve (AUC) of 0.744, 0.783, and 0.805, respectively. Impaired wound healing is characterized by pro-inflammatory MMP-2 and MMP-7. Serum and effluent concentrations of MMP-2, MMP-3, and MMP-7 can effectively predict the outcome of traumatic war wounds and can potentially provide decision-supportive, objective evidence for the timing of wound closure.

228. Matrix Metalloprotease (MMP) Expression is Associated With Wound Failure in Traumatic War Injuries

228. Matrix Metalloprotease (MMP) Expression is Associated With Wound Failure in Traumatic War Injuries

A Failure Mode for PWM Inverter-Fed AC Motors Due to the Antiresonance Phenomenon

A failure mode for pulsewidth-modulation inverter-fed ac motors due to the antiresonance phenomenon is introduced and investigated in this paper. At high frequencies, an ac motor behaves as a series RLC circuit with a resonance point, so-called antiresonance, typically above 1.0 MHz. If the voltage oscillation frequency caused by the reflected-wave phenomenon matches the motor antiresonance frequency, an amplified voltage will appear internally between the turns of the stator windings. This externally unobservable state can cause winding insulation failure in the ac motor. This phenomenon is experimentally verified using a rewound permanent-magnet motor with accessible taps along the stator windings, and the results are presented in this paper.

Choosing the correct side for Karydakis flap

Choosing the correct side for Karydakis flap in treatment of pilonidal disease in certain cases. When the cyst or diseased tissues appear deep into the opposite side it may create some annoying problems, like too thin skin edge, dead space and wound failure. Herein, a simple modification of skin incision marking to over-come this potential problem is described. This simple technical offer could be useful when dealing with sacrococcygeal pilonidal disease in daily surgical practice.

Delayed Wound Healing in Sacrococcygeal Pilonidal Sinus Coincides with an Altered Collagen Composition

Despite the availability of a range of surgical techniques, wound healing after pilonidal sinus surgery can be problematic. There is a paucity of scientific data regarding this problem, and Binnebosel et al. [1] should be congratulated for their careful study of wound healing after pilonidal sinus surgery. They have shown a clear relationship between disturbances of several components of the extracellular matrix at the excision margins and subsequent wound healing in patients who underwent pilonidal sinus surgery. What is the clinical relevance of these findings? It is not clear from this study whether the demonstrated differences in the extracellular matrix are due to a systemic problem in wound healing in a subgroup of patients or active inflammation at the excision margins. Would more radical excision back to ‘‘normal tissue’’ result in a higher rate of primary wound healing? There was a relatively high rate of failure of primary wound healing (27%) in this series. This may reflect the fact that wounds were closed in the midline and that no antibiotic prophylaxis was used. Techniques of pilonidal sinus surgery that avoid a midline wound have much lower reported rates of wound failure [2]. It would be interesting to see whether similar changes in the extracellular matrix are found in patients who have wider, eccentric excisions for pilonidal sinus, for example, the Karydakis procedure [3].

Ilio-lumbar Fixation—The Amrita Technique

Surgical technique description. To describe a surgical technique of ilio-lumbar fixation with iliac screws, which attempts to overcome some of the current limitations and technical difficulties associated with this surgery. The iliac screw technique, which is the most commonly used method of ilio-lumbar fixation, has certain limitations that need special consideration. These include soft tissue coverage, improving the strength of distal anchorage, reducing hardware prominence, avoiding complex 3-dimensional rod contouring, preventing neurologic injury, and acetabular violation. Over the past 5 years, we have used our technique in 8 patients (4 sacral tumors, 2 fracture dislocations, and 2 spinal tuberculosis). In 6 cases, the sacrum was not available for anchoring and hence was bypassed. The follow-up ranged from 3 to 54 months, and 5 patients had resumed normal activities. In 7 cases, the wound healed primarily and the solitary wound failure was in a previously irradiated skin. Other complications like neurologic deficit secondary to the procedure, acetabular violation, and implant failure were not encountered. Our technique of ilio-lumbar fixation provides a stable and simple alternative to reconstruct potentially devastating instability of the lumbosacral junction. The 2 iliac screws, when used as described, make the procedure technically easier, reduce the hardware prominence without compromising the stability to construct and provide adequate bone graft.

Frequency-Domain Model for Calculation of Voltage Distribution Through Random Wound Coils and Its Interaction With Stray Capacitances

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> Modern pulsewidth-modulation (PWM) low-voltage drives are recognized as one of the most demanding applications for a motor. Pulses facing motor terminals are responsible for turn-to-turn high electrical stresses that lead to unexpected failures in stator windings. In this paper, an accurate new model for frequency-domain voltage distribution calculation through random wound coils is presented. In addition to checking its applicability for varnished coils, the role of stray capacitances in turn-by-turn voltage propagation is analyzed as well. Model accuracy is proved using experimental data in an experimental test cell. Finally, the same model is applied successfully to real random wound coils inserted in a motor stator core, and the ability to change turn-to-turn electrical stresses by means of changes in stray capacitances values will be quantified. </para>

Wind Uplift Behavior of Mechanically Attached Single-Ply Roofing Systems: The Need for Correction Factors in Standardized Tests

In the United States, currently there are three consensus test methods for determining the wind uplift capacity of mechanically-attached single-ply roofing membrane systems. Each is based upon a specific specimen size and static loading regime. However, few studies have examined the relationship, if any, of failure loads among these methods. This study was conducted to determine the effects of varying specimen sizes on the static wind uplift performance or failure loads of mechanically-attached single-ply roofing membranes. Full-scale wind uplift pressure tests were performed in three phases, using six specimen sizes, and three membrane materials. The results were used to determine the minimum acceptable specimen sizes to be used for testing. In Phase 1, fastener failure loads were monitored, while in Phases 2 and 3, the failure experiments were repeated without measuring fastener loads. A significant difference in the apparent failure loads occurs among different specimen sizes for the same membrane materials. The results suggest that correction factors are necessary for comparing tests on different test beds and that the performance of membranes in the test chamber may not produce the same results on full scale structures.

QS191. Quantitative Bacteriology and Wound Failure in High Energy Penetrating War Injuries

Introduction: High-energy penetrating war injuries generate complex, contaminated wounds. Patients with these devastating injuries arrive at tertiary care military medical facilities heavily colonized with fastidious environmental bacteria, such as Acinetobacter baumannii. The cornerstone of war wound management remains surgical debridement to remove devitalized tissue and decrease bacterial colony counts. However, despite aggressive surgical management, some wounds fail, often secondary to ongoing infection.

Perineal wound complications after abdominoperineal resection.

Perineal wound complications following abdominoperineal resection (APR) is a common occurrence. Risk factors such as operative technique, preoperative radiation therapy, and indication for surgery (i.e., rectal cancer, anal cancer, or inflammatory bowel disease [IBD]) are strong predictors of these complications. Patient risk factors include diabetes, obesity, and smoking. Intraoperative perineal wound management has evolved from open wound packing to primary closure with closed suctioned transabdominal pelvic drains. Wide excision is used to gain local control in cancer patients, and coupled with the increased use of pelvic radiation therapy, we have experienced increased challenges with primary closure of the perineal wound. Tissue transfer techniques such as omental pedicle flaps, and vertical rectus abdominis and gracilis muscle or myocutaneous flaps are being used to reconstruct large perineal defects and decrease the incidence of perineal wound complications. Wound failure is frequently managed by wet to dry dressing changes, but can result in prolonged hospital stay, hospital readmission, home nursing wound care needs, and the expenditure of significant medical costs. Adjuvant therapies to conservative wound care have been suggested, but evidence is still lacking. The use of the vacuum-assisted closure device has shown promise in chronic soft tissue wounds; however, experience is lacking, and is likely due to the difficulty in application techniques.

QS194. Inflammatory Cytokine and Chemokine Expression Is Associated With Wound Failure in High Energy Penetrating War Injuries

QS194. Inflammatory Cytokine and Chemokine Expression Is Associated With Wound Failure in High Energy Penetrating War Injuries

A Stator and Rotor Fault Detection Technique for Induction Machines in Traction Applications for Electric or Hybrid Electric Vehicles

Three phase induction machines for traction applications in electric and hybrid electric vehicles can be used with a fixed gear due to the wide speed range enabled by field weakening. Although the induction machine is know as an extremely reliable and robust device, machine faults may occur. Machine faults which do not become detected may cause complete failure of the vehicle. Therefore, early detection of machine faults must be seen as important contribution for reliability and predictive maintenance. Stator winding and rotor failures, however, are a serious problem of squirrel cage induction machines. In an electric or a hybrid electric vehicle the traction machine may undergo severe thermal stress. Stator faults may occur much faster due to insulation breakdown or overload and are therefore more critical with respect to time. Such failures have therefore to be detected immediately after occurring. This paper presents fault detection techniques for stator and rotor faults of squirrel cage induction machines. Both the presented methods are model based techniques, competent to handle variable speed and load operating conditions.

A simplified scheme for induction motor condition monitoring

This work proposes a general scheme to detect induction motor fault by monitoring the motor current. The scheme is based on signal processing (predictive filters) and soft computing technique (fuzzy logic). The predictive filter is used in order to separate the fundamental component from the harmonic components. Fuzzy logic is used to identify the motor state. Finite element method (FEM) is utilised to generate virtual data that allows to test the proposed technique and foresee the change in the current under different motor conditions. A simple and reliable method for the detection of stator winding failures based on the phase current amplitudes is implemented and tested. The layout has been proved in MATLAB/SIMULINK, with both data from FEM motor simulation program and real measurements. The proposed method has the ability to work with variable speed drives and avoids the detailed spectral analysis of the motor current. This work shows the feasibility of spotting broken rotor bars, eccentricities and inter-turn short-circuit by monitoring the motor currents.

Single-stage Posterolateral Vertebrectomy for the Management of Metastatic Disease of the Thoracic and Lumbar Spine

Appropriate surgical management of spinal metastases combines maximal neural decompression with simultaneous immediate spinal column stabilization in the context of a paliative operation undertaken to improve patients' quality of life. We have used a single-stage posterolateral vertebrectomy (SPLV) for disease of the lumbar spine, combined with bilateral costotransversectomies in the thoracic spine, for these challenging cases. In this prospective cohort study of 96 consecutive patients with metastatic disease of the spinal column for we describe our surgical technique in detail, we examine our learning curve in its use and we analyze the long-term surgical and "quality of life" results in 42 patients who underwent SPLV. The mean and maximum operative blood loss was significantly lower for the SPLV group when compared with combined approaches. All patients either remained neurologically stable or had improved with surgery. Both the mean and the range visual analog scale scores were significantly improved after the SPLV. The SPLV was the only surgical approach to demonstrate a statistically significant improvement in Eastern Cooperative Oncology Group scores at 3 months after the surgery. Seventy-five percent of patients were alive at 6 months and 50% of patients survived for more than 12 months after the surgery. Eleven patients had a major complication (26%) with 9 (21%) patients required early reoperation, 7 of them for wound failure. Our data demonstrates that the SPLV represents a technically achievable improvement in surgical approach to spinal metastases when key parameters are examined. On the basis of these results, we recommend that the SPLV should be considered in all cases where resection of thoracic or lumbar spinal metastatic disease and reconstruction is contemplated.

Effect of Insulation Construction Bending on Stator Winding Failure

This paper investigates electrical breakdown of interconductor insulation, which presents an obstacle to the increase of the rated voltage of electrical machines as a means to improve efficiency of electrical energy exploitation. We have investigated a large number of samples searching for weak points in interconductor insulation along the coil of a high voltage asynchronous machine. The experiments were performed on lacquer-glass-glass-lacquer conductor insulation. Location of weak points and breakdown voltage levels have been determined.

Impulse Strength of Transformer Insulation With Nonstandard Waveshapes

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> While observing the impulse voltage distribution within a transformer winding, it can be seen that parts of the windings are excited by unidirectional and bidirectional oscillating voltages. The inter-turn and inter-disc winding failures are attributed to these oscillating voltages. Attempts are made to study the behavior of air, transformer oil, and oil-impregnated paper (OIP) insulation under these voltages. Small gaps of the order of a few millimeters with different electrode geometries are chosen to incorporate the extreme electrical field configurations in a practical transformer. Experimental voltage-time characteristics are obtained using statistical procedures. The Disruptive Effect Method is used to evaluate the insulation strength under unidirectional nonstandard impulse voltages. The insulation strength under bidirectional oscillating impulse voltages on these small insulation gaps are estimated using Unconditionally Sequential Approach. The ranges of the positive reinforcement time <formula formulatype="inline"><tex>$(t_{pr})$</tex> </formula> have been determined. The polarity effect on the breakdown due to bidirectional waveshape is duly accounted. </para>

The double-curvature masonry vaults of Eladio Dieste

The Uruguayan engineer Eladio Dieste developed an innovative construction method for wide-span roof structures. Known as Gaussian vaults, their double-curved geometry is based on the catenary resulting in mainly axial compressive forces. Whereas most thin wide-span roofs have been built using concrete, Dieste used brick, and unlike traditional masonry vaults, they are only one brick-layer in thickness. Typically the vaults have a low rise, the span-to-rise ratio is normally 8–10 and buckling is the likely mode of failure. Dieste used the curved surface of the vaults to resist buckling and developed design procedures to ensure their safety. In the present paper a brief background to Dieste's work is presented including his methods of analysis and the application is considered with reference to one of his larger projects, the warehouse at the docks in Montevideo, with a span of 45 m. Through an iterative mathematical procedure, Dieste formulated the critical loads of catenary arches into graphs. The method is compared with a finite-element study, which also considers the elastic deformations under self-weight, asymmetric loading owing to wind and ultimate failure owing to buckling.

Bone reconstruction following implantation of rhBMP‐2 and guided bone regeneration in canine alveolar ridge defects

Alveolar ridge aberrations commonly require bone augmentation procedures for optimal placement of endosseous dental implants. The objective of this study was to evaluate local bone formation following implantation of recombinant human bone morphogenetic protein-2 (rhBMP-2) in an absorbable collagen sponge (ACS) carrier with or without provisions for guided bone regeneration (GBR) as potential treatment modalities for alveolar augmentation. Surgically induced, large, mandibular alveolar ridge saddle-type defects (2 defects/jaw quadrant) in seven young adult Hound dogs were assigned to receive rhBMP-2/ACS, rhBMP-2/ACS combined with GBR (rhBMP-2/GBR), GBR, and surgery controls. The animals were euthanized at 12 weeks post-surgery when block sections of the defect sites were collected for histologic analysis. Clinical complications included swelling for sites receiving rhBMP-2 and wound failure with exposure of the barrier device for sites receiving GBR (4/6) or rhBMP-2/GBR (3/7). The radiographic evaluation showed substantial bone fill for sites receiving rhBMP-2/ACS, rhBMP-2/GBR, and GBR. In particular, sites receiving rhBMP-2/GBR presented with seroma-like radiolucencies. The surgery control exhibited moderate bone fill. To evaluate the biologic potential of the specific protocols, sites exhibiting wound failure were excluded from the histometric analysis. Sites receiving rhBMP-2/ACS or rhBMP-2/GBR exhibited bone fill averaging 101%. Bone fill averaged 92% and 60%, respectively, for sites receiving GBR and surgery controls. Bone density ranged from 50% to 57% for sites receiving rhBMP-2/ACS, GBR, or surgery controls. Bone density for sites receiving rhBMP-2/GBR averaged 34% largely due to seroma formation encompassing 13% to 97% of the sites. rhBMP-2/ACS appears to be an effective alternative to GBR in the reconstruction of advanced alveolar ridge defects. Combining rhBMP-2/ACS with GBR appears to be of limited value due to the potential for wound failure or persistent seromas.

Incisional Herniation Induces Decreased Abdominal Wall Compliance via Oblique Muscle Atrophy and Fibrosis

The purpose of this study is to measure abdominal wall myopathic histologic and mechanical changes during incisional herniation and its effect on incisional hernia repairs. Unloaded skeletal muscles undergo characteristic atrophic changes, including change in fiber type composition, decreased cross-sectional area, and pathologic fibrosis. We hypothesize that these atrophic changes decrease muscle elastic properties and may contribute to the high laparotomy wound failure rate observed following incisional hernia repair. A rat model of chronic incisional hernia formation was used. Failing midline laparotomy incisions developed into incisional hernias. Controls were uninjured and sham laparotomy (healed) groups. Internal oblique muscles were harvested for fiber typing, measurement of cross-sectional area, collagen deposition, and mechanical analysis. Mesh hernia repairs were performed on a second group of rats with chronic incisional hernias or acute anterior abdominal wall myofascial defects. The hernia group developed lateral abdominal wall shortening and oblique muscle atrophy. This was associated with a change in the distribution of oblique muscle fiber types, decreased cross-sectional area, and pathologic fibrosis consistent with myopathic disuse atrophy. These muscles exhibited significant decreased extensibility and increased stiffness. The healed (sham) laparotomy group expressed an intermediate phenotype between the uninjured and hernia groups. Recurrent hernia formation was most frequent in the chronic hernia model, and hernia repairs mechanically disrupted at a lower force compared with nonherniated abdominal walls. The internal oblique muscles of the abdominal wall express a pattern of changes consistent with those seen in chronically unloaded skeletal muscles. The internal oblique muscles become fibrotic during herniation, reducing abdominal wall compliance and increasing the transfer of load forces to the midline wound at the time of hernia repair.