Different intraoperative neuromonitoring modalities (mixed-nerve somatosensory-evoked potential M-SSEP, dermatomal somatosensory-evoked potential D-SSEP, compound motor-evoked potential CMEP, ...electromyography EMG, and the Hoffmann reflex H-reflex) have been developed for early detection of nerve root injury, for timely revision, and for damage reduction. In this study, we discuss the advantages and disadvantages of M-SSEP and D-SSEP by reviewing experimental evidence from animal models and clinical practice.
Introduction
Treating a terrible triad injury of the elbow remains a challenge for orthopedic surgeons, especially in elderly patients due to the poor quality of the surrounding soft tissue and bony ...structures. In the present study, we propose a treatment protocol using an internal joint stabilizer through a single posterior approach and analyze the clinical results.
Materials and Methods
We retrospectively reviewed 15 elderly patients with terrible triad injuries of the elbow who underwent our treatment protocol from January 2015 to December 2020. The surgery involved a posterior approach, identification of the ulnar nerve, bone and ligament reconstruction, and the application of the internal joint stabilizer. A rehabilitation program was initiated immediately after the operation. Surgery-related complications, elbow range of motion (ROM), and functional outcomes were evaluated.
Results
The mean follow-up period was 21.7 months (range, 16-36 months). ROM at the final follow-up was 130° in extension to flexion and 164° in pronation to supination. The mean Mayo Elbow Performance Score was 94 at the final follow-up. Major complications included breaking of the internal joint stabilizer in 2 patients, transient numbness over the ulnar nerve territory in one, and local infection due to irritation of the internal joint stabilizer in one.
Conclusions
Although the current study involved only a small number of patients and the protocol comprised two stages of operation, we believe that such a technique may be a valuable alternative for the treatment of these difficult cases.
Level of Clinical Evidence
4.
Spinal somatosensory-evoked potentials (SSEPs), elicited by mixed nerve and dermatomal stimulation, and compound evoked muscle potentials (CMAPs), elicited by lower thoracic interspinous space ...stimulation, were recorded in rats that underwent single nerve root transection.
To investigate and compare the effects of single nerve root transection using various electrophysiological models and to define a monitoring strategy that can easily and accurately predict compromise caused by a single lumbosacral nerve root injury.
Neuromonitoring is an important and effective preventive measure against neurologic complications during spinal surgery, but monitoring the lumbosacral nerve roots is not well established.
Rats received (Group I) a sham operation or had the (Group II) left L4, (Group III) L5, or (Group IV) L6 nerve root transected. SSEP were recorded at the thoracolumbar junction following stimulation of the sciatic nerve (M-SSEP) and the L5 dermatome (D-SSEP). CMAP was recorded at the intrinsic muscles of the foot by electrical stimulation in the lower thoracic spinal cord. Potentials recorded before and after a single nerve root transection were compared and correlated with clinical status by walking-track analysis 1 week later.
Relative amplitudes in Group II were 54.1% (M-SSEP), 84.6% (D-SSEP), and 85.5% (CMAP); 25.2% (M-SSEP), 66.5% (D-SSEP), and 85.8% (CMAP) in Group III; and 66.5% (M-SSEP), 95.5% (D-SSEP), and 23.2% (CMAP) in Group IV. M-SSEP is sensitive but not specific to single nerve root injury. D-SSEP and CMAP are less sensitive but more specific.
Injury to a single lumbosacral nerve root is diagnosed more easily with M-SSEP. With D-SSEP and CMAP, it was possible to differentiate the lesioned nerve root by stimulating the primary dermatome or recording from the innervated muscle. M-SSEP is an easy-sampling and appropriate tool for screening nerve root injury; its poor specificity may be overcome by using D-SSEP and CMAP in addition. Optimal monitoring of the lumbosacral nerve roots during lumbar spinal surgery requires the administration of M-SSEP, D-SSEP, and CMAP to provide independent verification of lumbosacral nerve root integrity and to allow detection of the occasional injuries that selectively affect either the sensory or motor system.
The role of adenosine (ADO) in the regulation of glucose homeostasis is not clear. In the current study, we used A1-ADO receptor (A1AR)-deficient mice to investigate the role of ADO/A1AR signaling ...for glucose homeostasis.
After weaning, A1AR(-/-) and wild-type mice received either a standard diet (12 kcal% fat) or high-fat diet (HFD; 45 kcal% fat). Body weight, fasting plasma glucose, plasma insulin, and intraperitoneal glucose tolerance tests were performed in 8-week-old mice and again after 12-20 weeks of subsequent observation. Body composition was quantified by magnetic resonance imaging and epididymal fat-pad weights. Glucose metabolism was investigated by hyperinsulinemic-euglycemic clamp studies. To describe pathophysiological mechanisms, adipokines and Akt phosphorylation were measured.
A1AR(-/-) mice were significantly heavier than wild-type mice because of an increased fat mass. Fasting plasma glucose and insulin were significantly higher in A1AR(-/-) mice after weaning and remained higher in adulthood. An intraperitoneal glucose challenge disclosed a significantly slower glucose clearance in A1AR(-/-) mice. An HFD enhanced this phenotype in A1AR(-/-) mice and unmasked a dysfunctional insulin secretory mechanism. Insulin sensitivity was significantly impaired in A1AR(-/-) mice on the standard diet shortly after weaning. Clamp studies detected a significant decrease of net glucose uptake in A1AR(-/-) mice and a reduced glucose uptake in muscle and white adipose tissue. Effects were not triggered by leptin deficiency but involved a decreased Akt phosphorylation.
ADO/A1AR signaling contributes importantly to insulin-controlled glucose homeostasis and insulin sensitivity in C57BL/6 mice and is involved in the metabolic regulation of adipose tissue.
Abstract Background Context Autonomic dysreflexia (AD) usually presents with a significant increase in blood pressure, and uncontrollable autonomic response to stimuli below the level of spinal cord ...injury (SCI). Purpose This study analyzed the vasomotor function and molecular changes in the peripheral arteries below the lesion of SCI to characterize the mechanism of autonomic dysreflexia. Study Design This was a randomized experimental study in rats. Methods Contusive SCI was induced using a force-calibrated weight-drop device at the T10 level in anesthetized rats. Two weeks after severe SCI, blood flow in the femoral arteries was measured, and the vasomotor function and expression of α1-adrenergic receptors were analyzed. Results Blood flow in the femoral artery was significantly reduced in rats with SCI (8.0±2 vs. 17.5±4 mL/min, SCI vs. control, respectively; p=.016). The contraction responses of femoral artery segments to cumulative addition of α1-adrenergic agonist phenylephrine were significantly enhanced in rats with SCI. Expression of α1-adrenergic receptor was upregulated in the medial layer of femoral artery vascular homogenates of these rats. Conclusion Our study provides evidence demonstrating that prolonged denervation below the lesion level following SCI results in a compensatory increased expression of α1-adrenergic receptors in the arterial smooth muscle layer, thereby enhancing the responsiveness to α1-adrenergic agonist and potentiating the development of AD.
Introduction
Internal fixation is the treatment of choice for subtrochanteric fractures in most conditions. However, it may be an unsuitable procedure for patients with poor health status, ...osteomyelitis, and surrounding soft tissue compromise. This study aimed to ascertain the viability and reliability of using external locking plate fixation for these difficult cases.
Methods
Eleven patients with femoral subtrochanteric fractures who received external locking plate fixation in our institute from January 2014 to December 2019 were enrolled in our study. The bone union time, wound complication, alignment, and necessity for narcotic agents were evaluated.
Results
The average length of follow-up was 17.5 months (range, 14-26 months). The mean time for bone union was 17.7 weeks (range, 15-21 weeks). The indications included poor health condition, soft tissue compromise, and post-operative osteomyelitis. Pin tract infection was noted in two patients who were treated successfully with oral antibiotics administration and removal of the involved screws. Osseous union with varus deformity <10° was achieved in all patients except one. Three patients required an orally administered pain killer at the final visit. The average Harris Hip Score at one year post-operatively was 66.6 (range, 49-80).
Conclusions
Although the current study only involved 11 patients, we believe that our method may serve as a valuable alternative for the treatment of a femoral subtrochanteric fracture in selected cases.
Level of Evidence
Level IV, retrospective case series
Aortic coarctation complicated with spinal artery aneurysm rupture is exceptionally rare and can be source of intraspinal hemorrhage with markedly poor prognosis. A 21-year-old man visited the ...emergency department because of chest and back pain along with immobility of bilateral lower limbs immediately after he woke up in the morning. Complete flaccid paraplegia and hypoesthesia in dermatome below bilateral T3 level and pain over axial region from neck to lumbar region were noted. A computed tomography excluded aortic dissection. Magnetic resonance imaging revealed a fusiform lesion involving the anterior epidural space from C7 to T2 level suspected of epidural hemorrhage, causing compression of spinal cord. He started intravenous corticosteroid but refused operation concerning the surgical benefits. Severe chest pain occurred with newly onset right bundle branch block that developed the other day. Coronary artery angiography revealed myocardial bridge of left anterior descending coronary artery at middle third and coarctation of aorta. He underwent thoracic endovascular aortic repair uneventfully. The patient was hemodynamically stable but with slow improvement in neurologic recovery of lower limbs. Aortic coarcation can cause paralysis by ruptured vascular aneurysms with spinal hemorrhage and chest pain that mimics acute aortic dissection. A history of hypertension at young age and aortic regurgitated murmurs may serve as clues for further diagnostic studies. Cautious and prudent evaluation and cross disciplines cares are essential for diagnosis and successful management of the disease.
For many years, brain ischemia has been known to be a leading cause of adult neurological disorder. In particular, many reports have shown that hyperexcitability of neurons and inflammatory response ...of the glia induced by ischemic reperfusion (I/R) determine the fate of cells in the ischemic core and the penumbra region. Although there are many reports on the activation and roles of signal transducer and activator of transcription (STAT) proteins (STAT1, STAT3, and STAT5) during hyperexcitation in the neuron and inflammation occurring following I/R, the temporal and spatial activation of STAT6 protein in the ischemic cortex still remain elusive. In this study, using a transient rat middle cerebral artery occlusion model, we primarily investigated the time-course expression of the phosphorylated STAT6 (pSTAT6) in the ischemic core region following I/R, which was compared with that of pSTAT3. We found that pSTAT6 significantly decreases at 1 and 12 h following I/R, whereas pSTAT3 markedly increases at each follow-up time point. In addition, the level of pSTAT6 is reduced in the ischemic core in comparison with the penumbra region at 12 h following I/R. However, there is no significant difference in pSTAT3 expression between the ischemic core and the penumbra. Taken together, our data suggest that pSTAT6 and pSTAT3 are modulated differently following I/R during ischemic stroke.
Background Genetic syndromes, especially 22q11 deletion (del22q11) syndrome, are common in patients with pulmonary atresia and ventricular septal defect (PA-VSD), but their association with long-term ...outcomes varies. The purpose of this study was to evaluate the long-term outcome after complete repair of PA-VSD and to determine the impact of genetic syndromes. Methods We reviewed our experience of 125 patients with PA-VSD who received primary or staged repair between 1978 and 2010. Evaluations for genetic syndromes included clinical features, cytogenetic analysis, and fluorescence in situ hybridization or multiplex ligation-dependent probe amplification. Results Genetic syndromes were documented in 26 patients (20.8%), including del22q11 in 16 patients, trisomy 21 in 2 patients, and other syndromes in 8 patients. The prevalence of hypoplastic pulmonary arteries was not significantly different between the syndromic and nonsyndromic groups. After 1,069 patient-years of follow-up, 20-year survival was 90% ± 6% in patients without syndromes and 14% ± 23% in patients with syndromes ( p < 0.01). Multivariate analysis identified the presence of a genetic syndrome as an important risk factor for hospital and late mortality. Subgroup analysis showed that genetic syndromes other than del22q11 were associated with worse outcome. The rate of 10-year freedom from cardiac reintervention after repair was 53% ± 11%, with hypoplastic pulmonary arteries before repair as a major risk factor ( p = 0.02). Conclusions Genetic syndromes significantly affect survival after repair of PA-VSD, whereas genetic syndromes do not represent additional risk for reintervention. Repair is feasible in patients with syndromes, but suboptimal long-term outcome should be addressed when counseling parents.
Background Unstable distal clavicle fractures often need surgical treatment. This report describes a new intramedullary extra-articular Knowles pin fixation method to treat these unstable fractures. ...Materials and methods Twelve patients with unstable distal clavicle fractures (Neer type II) had surgery with intramedullary extra-articular Knowles pin fixation. We retrospectively reviewed clinical results for pain, shoulder function, and range of motion, as well as radiographic results, for this institutional review board–approved study. Each patient’s operated arm was in a sling for 4 weeks postoperatively. The University of California, Los Angeles shoulder rating scale score was used to evaluate shoulder function. Results All patients showed radiographically confirmed bony union. The mean period required for healing was 11.5 weeks, and patients were followed up for 6 to 24 months (mean, 15.2 months), during which University of California, Los Angeles scores (mean, 33.9) indicated good clinical results. Three patients had the complication of proximal or distal skin irritation caused by the thread and hub of the Knowles pin. Conclusions The Knowles pin fixation method is useful for treating unstable distal clavicle fractures. However, sufficient familiarity with the technique and careful preoperative planning to determine the appropriate length of the pin are necessary to prevent complications and to effect a high union rate.
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