Haemodynamic and Pulmonary Function Following Mitral Valve Replacement

Haemodynamic and pulmonary functional data were recorded in 10 patients undergoing mitral valve replacement with the Björk—Shiley tilting disc valve. Within 48 hours after surgery, mean pulmonary capillary wedge pressure decreased from 27.9 mmHg pre-operatively to 14.3 mmHg, while mean pulmonary arterial pressure (PAP) remained elevated at 31.3 mmHg. Although the cardiac index rose to 2.9 1/min·m², pulmonary vascular resistance (PVR) increased in the first 3 days. PAP and PVR had returned to normal at late control 6–10 months postoperatively. Vital capacity and forced expiratory volume in one second both showed a mean improvement of 15% at late control. Simple spirometry may be a valid indirect method of assessing easily and objectively the efficacy of mitral valve replacement.     

Tripled semitendinosus anterior cruciate ligament reconstruction with Endobutton fixation: A 2-3-year follow-up study of 35 patients

We evaluated the clinical outcome of tripled semitendinosus tendon ACL reconstruction with femoral Endobutton (Acufex, Smith&Nephew, Andover, MA) and tibial Suture Washer (Acufex, Smith&Nephew, Andover, MA) (n 29) or post screw fixation (n 6) in 35 patients on an average of 28 (20-37) months after surgery. On the basis of IKDC criteria, 22 patients showed a normal or nearly normal knee function and 25 patients had a KT 1000 maximal manual side-to-side difference of &#104 5 mm at follow-up. Subjectively, 28 patients graded their knee function as normal or nearly normal. The average Lysholm score was 88 points, average OAK score 90 points and average modified HSS score 93 points. 19 patients reached their preinjury level of activity at follow-up. The postoperative Lachman test was &#104 1+ in 24 patients and 24 patients also showed an absent pivot shift. Significant bone tunnel enlargement occurred in 26 patients on the femoral side and in 23 patients on the tibial side. We found no correlation between bone tunnel enlargement and clinical outcome. The clinical outcome of tripled semitendinosus tendon ACL reconstruction with Endobutton fixation on the femoral side was not entirely satisfactory. The procedure was associated with a high incidence of bone tunnel enlargement in this series.     

Electrical impedance myography in the diagnosis of radiculopathy

Introduction: We sought to determine whether electrical impedance myography (EIM) could serve as a diagnostic procedure for evaluation of radiculopathy. Methods: Twenty‐seven patients with clinically and radiologically diagnosed cervical or lumbosacral radiculopathy who met a “gold standard” definition underwent EIM and standard needle electromyography (EMG) of multiple upper or lower extremity muscles. Results: EIM reactance values revealed consistent reductions in the radiculopathy‐affected myotomal muscles as compared with those on the unaffected side; the degree of asymmetry was associated strongly with the degree of EMG abnormality (P < 0.001). EIM had a sensitivity of 64.5% and a specificity of 77.0%; in comparison, EMG had a sensitivity of 79.7% but a specificity of 69.7%. Conclusions: These findings support the potential for EIM to serve as a new non‐invasive tool to assist in diagnosis of radiculopathy; however, further refinement of the technique is needed for this specific application. Muscle Nerve 48:800–805, 2013     

Motor unit potential induced repetitive discharges (MIRDs): Description of an unusual iterative discharge

Introduction: Repetitive discharges may be recorded during nerve conduction studies (NCS) or during needle electromyography in a muscle at rest. Repetitive discharges that occur during voluntary activation and are time‐locked to voluntary motor unit potentials (MUP) have not been described. Methods: Retrospective review of motor unit potential induced repetitive discharges (MIRDs) identified in the EMG laboratory. Characteristics of each MIRD, patient demographics, other EMG findings in the same muscle, and electrophysiological diagnosis were analyzed. Results: MIRDs were observed in 15 patients. The morphology and number of spikes and duration of MIRDs varied. The discharges fired at rates of 50–200 Hz . All but 2 patients had EMG findings of a chronic neurogenic disorder. Conclusions: MIRDs are rare iterative discharges time‐locked to a voluntary MUP. The pathophysiology of MIRDs is unclear, but their presence may indicate a chronic neurogenic process. Muscle Nerve 48 : 977–979, 2013     

Spontaneous electromyographic activity of the tongue in amyotrophic lateral sclerosis

Introduction: Detection of denervation in muscles in the craniobulbar area is important to assure widespread lower motor neuron involvement in the diagnosis of amyotrophic lateral sclerosis (ALS). The value of spontaneous activity analysis in needle electromyography (EMG) of the tongue has been questioned in the recent literature. Methods: Spontaneous activity in the tongue and sternocleidomastoid (SCM) muscles was reviewed retrospectively in 17 ALS patients. Results: Needle EMG showed spontaneous activity in the tongue in 14 of 17 patients (82%) and in 6 patients of 17 (35%) in SCM. Spontaneous EMG activity in the tongue was found in patients with and without bulbar symptoms. Conclusions: Needle EMG is a valuable method for assessing clinical and subclinical involvement of the tongue in patients with bulbar and limb onset ALS. Adequate relaxation of the tongue is a prerequisite for proper spontaneous activity recording. Muscle Nerve, 48: 296–298, 2013     

A novel electrodiagnostic assessment of the laryngeal closure reflex

Introduction: We describe a novel, clinically applicable conduction study of the laryngeal nerves. Methods: Seventeen normal volunteer subjects were included. Activation of the sensory territory of the superior laryngeal nerve was performed by administration of low level brief electrical stimuli. The laryngeal closure reflex (LCR) evoked by this stimulus was recorded by needle electrodes. Mean minimal latencies were calculated for each response, and proposed values for the upper limit of normal were determined. Results: Uniform, consistent early ipsilateral responses and late bilateral responses, which exhibit greater variation in latency and morphology, were recorded. Significant side‐to‐side differences in latencies were observed, consistent with the length discrepancy between right and left recurrent laryngeal nerves. Conclusions: This technique yields clear, quantifiable data regarding neurologic integrity of laryngeal function, heretofore unobtainable in the clinical setting. This study may yield clinically relevant information regarding severity and prognosis in patients with laryngeal neuropathic injury. Muscle Nerve 47:432‐436, 2013     

Age‐associated changes in muscle activity during isometric contraction

Introduction: We investigated the effect of age on the complexity of muscle activity and the variance in the force of isometric contraction. Methods: Surface electromyography (sEMG) from biceps brachii muscle and force of contraction were recorded from 96 subjects (20–70 years of age) during isometric contractions. Results: There was a reduction in the complexity of sEMG associated with aging. The relationship of age and complexity was approximated using a bilinear fit, with the average knee point at 45 years. There was an age‐associated increase in the coefficient of variation (CoV) of the force of muscle contraction, and this increase was correlated with the decrease in complexity of sEMG (r² = 0.76). Conclusions: There was an age‐associated increase in CoV and also a reduction in the complexity of sEMG. The correlation between these 2 factors can be explained based on the age‐associated increase in motor unit density. Muscle Nerve 47: 545–549, 2013     

Spasticity,weakness, force variability,and sustained spontaneous motor unit discharges of resting spastic–paretic biceps brachii muscles in chronic stroke

Introduction: The purpose of our study was to examine relations among spasticity, weakness, force variability, and sustained spontaneous motor unit discharges in spastic–paretic biceps brachii muscles in chronic stroke. Methods: Ten chronic stroke subjects produced submaximal isometric elbow flexion force on impaired and non‐impaired sides. Intramuscular EMG (iEMG) was recorded from biceps and triceps brachii muscles. Results: We observed sustained spontaneous motor unit discharges in resting biceps on iEMG. Spontaneous discharges increased after voluntary activation only on the impaired side. The impaired side had greater matching errors and greater fluctuations in isometric force. Spontaneous discharges were not related functionally to spasticity, force variability, or weakness. However, greater strength on the impaired side correlated with less force variability. Conclusion: Weakness rather than spasticity is a main factor interfering with voluntary force control in paretic–spastic biceps brachii muscles in chronic stroke. Muscle Nerve, 2013