Negative Pressure Wound Therapy for Gas Gangrene of the Fingertip with Prolonged Infection.

Background: We encountered a case of infected soft tissue defect of the fingertip treated using negative pressure wound therapy (NPWT). The development of NPWT was started in the early 1990s, and it is a relatively new treatment method included in insurance coverage in Japan in 2010. NPWT is used for intractable wounds; some reports have examined its use on infected wounds. However, to the best of our knowledge, no study has examined its use on infected fingertip wounds. Methods: A patient with an infected soft tissue defect in the fingertip whose epithelialization period was prolonged despite continued antibiotic therapy was treated using NPWT in combination. Results: After NPWT was started, signs of infection and wound granulation were good. Additionally, completion of epithelialization was confirmed 7 weeks after NPWT started. Conclusions: Conventionally, skin flap or graft by hand surgeons have been performed on fingertip soft tissue defects with infection. NPWT does not require specialized and advanced surgical techniques; treatment for infected soft tissue defects can be administered by anyone if they have the required skills. In conclusion, NPWT may be considered a suitable alternative when treatment options such as flaps and skin grafts are not feasible.

Detection of Sacral Fractures on Radiographs Using Artificial Intelligence.

Sacral fractures are often difficult to diagnose on radiographs. Computed tomography (CT) and magnetic resonance imaging (MRI) can improve the detection rate but cannot always be performed. The accuracy of artificial intelligence (AI) in detecting orthopaedic fractures is now comparable with that of orthopaedic specialists. However, the ability of AI to detect sacral fractures has not been investigated, to our knowledge. We hypothesized that the ability to detect sacral fractures on radiographs could be improved by using AI, and aimed to develop an AI model to detect sacral fractures accurately on radiographs with better accuracy than that of orthopaedic surgeons. Methods: Subjects were patients with suspected pelvic fractures for whom radiographs and CT scans had been obtained. The radiographs were labeled according to sacral fracture status based on CT results. The data set was divided into a training set (2,038 images) and a test set (200 images). Eight convolutional neural network (CNN) models were trained using the training set. Post-trained models were used to evaluate their discrimination ability. The detection ability of 4 experienced orthopaedic surgeons was also measured using the same test set. The results of fracture assessment by the orthopaedic surgeons were compared with those of the 3 CNNs with the greatest area under the receiver operating characteristic curve. Results: Among the 8 trained models, the highest areas under the curve were for InceptionV3 (0.989), Xception (0.987), and Inception ResNetV2 (0.984). The detection rate was significantly higher for these 3 CNNs than for the orthopaedic surgeons. Conclusions: By enhancing the processing of probabilistic tasks and the communication of their results, AI may be better able to detect sacral fractures than orthopaedic surgeons. Level of Evidence: Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Involvement of Parkin-mediated mitophagy in the pathogenesis of chronic obstructive pulmonary disease-related sarcopenia.

BACKGROUND: Sarcopenia is characterized by the loss of skeletal muscle mass and strength and is associated with poor prognosis in patients with chronic obstructive pulmonary disease (COPD). Cigarette smoke (CS) exposure, a major cause for COPD, induces mitochondrial damage, which has been implicated in sarcopenia pathogenesis. The current study sought to examine the involvement of insufficient Parkin-mediated mitophagy, a mitochondrion-selective autophagy, in the mechanisms by which dysfunctional mitochondria accumulate with excessive reactive oxygen species (ROS) production in the development of COPD-related sarcopenia. METHODS: The involvement of Parkin-mediated mitophagy was examined using in vitro models of myotube formation, in vivo CS-exposure model using Parkin-/- mice, and human muscle samples from patients with COPD-related sarcopenia. RESULTS: Cigarette smoke extract (CSE) induced myotube atrophy with concomitant 30% reduction in Parkin expression levels (P < 0.05). Parkin-mediated mitophagy regulated myotube atrophy by modulating mitochondrial damage and mitochondrial ROS production. Increased mitochondrial ROS was responsible for myotube atrophy by activating Muscle Ring Finger 1 (MuRF-1)-mediated myosin heavy chain (MHC) degradation. Parkin-/- mice with prolonged CS exposure showed enhanced limb muscle atrophy with a 31.7% reduction in limb muscle weights (P < 0.01) and 2.3 times greater MuRF-1 expression (P < 0.01) compared with wild-type mice with concomitant accumulation of damaged mitochondria and oxidative modifications in 4HNE expression. Patients with COPD-related sarcopenia exhibited significantly reduced Parkin but increased MuRF-1 protein levels (35% lower and 2.5 times greater protein levels compared with control patients, P < 0.01 and P < 0.05, respectively) and damaged mitochondria accumulation demonstrated in muscles. Electric pulse stimulation-induced muscle contraction prevented CSE-induced MHC reduction by maintaining Parkin levels in myotubes. CONCLUSIONS: Taken together, COPD-related sarcopenia can be attributed to insufficient Parkin-mediated mitophagy and increased mitochondrial ROS causing enhanced muscle atrophy through MuRF-1 activation, which may be at least partly preventable through optimal physical exercise.

Distribution of hounsfield unit values in the pelvic bones: a comparison between young men and women with traumatic fractures and older men and women with fragility fractures: a retrospective cohort study.

BACKGROUND: The fixation strength of bone screws depends on bone mineral density (BMD), so it is important to evaluate bone strength at fracture sites. Few studies have investigated BMD in the pelvis. The aims of this study were to measure the regional Hounsfield unit (HU) values in the cancellous bone of the acetabulum and pelvic ring and to compare these values between young and older patients. METHODS: This study enrolled young patients with high-energy trauma (aged 20-44 years; young group) and older patients with low-energy trauma (aged 65-89 years; older group). Patients without pelvic computed tomography (CT) scans, those with pelvic bone implants, and those who died were excluded. The HU values on the contralateral (non-fractured) side of the pelvis were measured on CT scans. The CT data were divided into 7 areas: the pubic bone, the anterior and posterior walls and roof of the acetabulum, the ischial tuberosity, the body of the ilium, and the third lumbar vertebra. The HU values in each area were compared between the young and older groups. RESULTS: Sixty-one young patients and 154 older patients were included in the study. The highest HU value was in the roof of the acetabulum regardless of age and sex. HU values were significantly higher in the ischial tuberosity and body of the ilium and lower in the pubic bone and anterior wall. The HU values in all pelvic areas were significantly lower in the older group than in the young group, especially in the anterior area. CONCLUSIONS: HU values in the 6 pelvic areas were not uniform and were strongly related to load distribution. The HU distribution and age-related differences could explain the characteristic causes and patterns of acetabular fractures in the older and may help in surgical treatment.

Factors affecting spine-femur discordance in the percentage of young adult mean on dual-energy X-ray absorptiometry in the elderly population: a retrospective study.

BACKGROUND: Several retrospective studies have reported spine-femur discordance in bone mineral density (BMD) values. However, the average age of individuals in these studies was the mid-50s, which is younger than the typical age of individuals requiring treatment for primary osteoporosis. Therefore, we aimed to investigate factors associated with discordance in the percentage of young adult mean (YAM) between the lumbar spine and femoral neck in the elderly population. METHODS: We evaluated 4549 dual-energy X-ray absorptiometry (DXA) measurements obtained from 2161 patients (269 men and 1892 women) between January 2014 and December 2017 at our hospital. For individuals with more than one eligible set of measurements, the first record was used. We investigated each patient's age, sex, body mass index, current smoking status, alcohol consumption, use of steroids, presence of diabetes mellitus, and presence of rheumatoid arthritis. RESULTS: The mean age of the patients was 76.4 ± 8.9 years. Older age (p <  0.001), male sex (p <  0.001), and diabetes mellitus (p = 0.007) were significantly associated with spine-femur discordance in the percentage of YAM. CONCLUSION: The frequency and magnitude of spine-femur discordance in the percentage of YAM from DXA scans increased with age. Notably, more than 77.4% of patients in their 90s had spine-femur discordance > 10% of YAM. Furthermore, the frequency of spine-femur discordance was higher in men and in patients with diabetes mellitus, suggesting that the percentage of YAM at the lumbar spine may not be reliable for diagnosis of osteoporosis in patients with these factors.

Shear Wave Velocity to Evaluate the Effect of Botulinum Toxin on Post-Stroke Spasticity of the Lower Limb.

(1) Background: The evaluation of muscles with spasticity using ultrasound elastography has attracted attention recently, and the shear wave velocity (SWV) technique can measure the mechanical properties of tissues objectively and quantitatively. The purpose of this study was to evaluate the effect of using SWV to assess the effect of Botulinum toxin type A (BoNT-A) treatment in adult patients with post-stroke lower limb spasticity. (2) Methods: We assessed the modified Ashworth Scale, the modified Tardieu Scale, and SWV at rest and after stretching before and at 1 month after BoNT-A treatment in 10 adult participants with post-stroke lower limb spasticity. (3) Results: Significant changes in SWV of the ankle joint in maximum dorsiflexion to the extent possible (SWV stretched) were observed after BoNT-A treatment. SWV stretched was positively correlated with joint range of motion. Participants whose joint range of motion did not improve (i.e., gastrocnemius medialis muscle (GCM) extension distance did not change) had significantly more reductions in SWV stretched after BoNT-A treatment. (4) Conclusions: Our results suggest that the SWV measurements may serve as a quantitative assessment to determine the effect of the BoNT-A treatment in adult stroke patients. SWV measurements to assess GCM spasticity should consider the effects of tension, material properties and activation level of muscles. The challenge is to measure SWV with matching limb positions in patients without contractures.

Acute Compartment Syndrome of the Upper Extremity in Acquired Hemophilia A: A Case Report and Literature Review.

CASE: Acute compartment syndrome (ACS) with acquired hemophilia A (AHA) is rare and has no established treatment strategy. A 64-year-old woman presented with a giant hematoma in the rectus abdominis. Laboratory findings included decreased hemoglobin and increased activated partial thromboplastin time. Arterial embolization was performed for hemostasis. After catheter removal, she developed severe arm pain and numbness with blistering. Fasciotomy was performed to decrease intracompartmental pressure. Laboratory investigations revealed decreased factor VIII (FVIII) activity and increased FVIII inhibitor. AHA was diagnosed and treated with immunosuppressive and FVIII inhibitor-bypassing agents. CONCLUSIONS: Fasciotomy should be performed promptly if ACS with AHA is suspected.

Depressed contractile performance and reduced fatigue resistance in single skinned fibers of soleus muscle after long-term disuse in rats.

Long-term disuse results in atrophy in skeletal muscle, which is characterized by reduced functional capability, impaired locomotor condition, and reduced resistance to fatigue. Here we show how long-term disuse affects contractility and fatigue resistance in single fibers of soleus muscle taken from the hindlimb immobilization model of the rat. We found that long-term disuse results in depression of caffeine-induced transient contractions in saponin-treated single fibers. However, when normalized to maximal Ca(2+)-activated force, the magnitude of the transient contractions became similar to that in control fibers. Control experiments indicated that the active force depression in disused muscle is not coupled with isoform switching of myosin heavy chain or troponin, or with disruptions of sarcomere structure or excessive internal sarcomere shortening during contraction. In contrast, our electronmicroscopic observation supported our earlier observation that interfilament lattice spacing is expanded after disuse. Then, to investigate the molecular mechanism of the reduced fatigue resistance in disused muscle, we compared the inhibitory effects of inorganic phosphate (Pi) on maximal Ca(2+)-activated force in control vs. disused fibers. The effect of Pi was more pronounced in disused fibers, and it approached that observed in control fibers after osmotic compression. These results suggest that contractile depression in disuse results from the lowering of myofibrillar force-generating capacity, rather than from defective Ca(2+) mobilization, and the reduced resistance to fatigue is from an enhanced inhibitory effect of Pi coupled with a decrease in the number of attached cross bridges, presumably due to lattice spacing expansion.

Troponin and titin coordinately regulate length-dependent activation in skinned porcine ventricular muscle.

We investigated the molecular mechanism by which troponin (Tn) regulates the Frank-Starling mechanism of the heart. Quasi-complete reconstitution of thin filaments with rabbit fast skeletal Tn (sTn) attenuated length-dependent activation in skinned porcine left ventricular muscle, to a magnitude similar to that observed in rabbit fast skeletal muscle. The rate of force redevelopment increased upon sTn reconstitution at submaximal levels, coupled with an increase in Ca2+ sensitivity of force, suggesting the acceleration of cross-bridge formation and, accordingly, a reduction in the fraction of resting cross-bridges that can potentially produce additional active force. An increase in titin-based passive force, induced by manipulating the prehistory of stretch, enhanced length-dependent activation, in both control and sTn-reconstituted muscles. Furthermore, reconstitution of rabbit fast skeletal muscle with porcine left ventricular Tn enhanced length-dependent activation, accompanied by a decrease in Ca2+ sensitivity of force. These findings demonstrate that Tn plays an important role in the Frank-Starling mechanism of the heart via on-off switching of the thin filament state, in concert with titin-based regulation.

Disuse-induced preferential loss of the giant protein titin depresses muscle performance via abnormal sarcomeric organization.

Persistent muscle weakness due to disuse-associated skeletal muscle atrophy limits the quality of life for patients with various diseases and individuals who are confined to bed. Fibers from disused muscle exhibit a marked reduction in active force production, which can exacerbate motor function, coupled with the well-known loss of muscle quantity. Despite recent understanding of the signaling pathways leading to the quantity loss, the molecular mechanisms of the depressed qualitative performance still remain elusive. Here we show that long-term disuse causes preferential loss of the giant sarcomere protein titin, associated with changes in physiologic muscle function. Ca(2+) sensitivity of active force decreased following 6 wk of hindlimb immobilization in the soleus muscle of the rat, accompanied by a shift in the length-active force relationship to the shorter length side. Our analyses revealed marked changes in the disused sarcomere, with shortening of thick and thin filaments responsible for altered length dependence and expansion of interfilament lattice spacing leading to a reduction in Ca(2+) sensitivity. These results provide a novel view that disuse-induced preferential titin loss results in altered muscle function via abnormal sarcomeric organization.