Neuromuscular Insufficiency Research Articles

A Randomized Comparison of the Biomechanical Effect of Two Commercially Available Rocker Bottom Shoes to a Conventional Athletic Shoe During Walking in Healthy Individuals

Rocker bottom shoes have recently gained considerable popularity, likely in part because of the many purported benefits, including reducing joint loading and toning muscles. Scientific inquiry about these benefits has not kept pace with the increased usage of this shoe type. A fundamental premise of rocker bottom shoes is that they transform hard, flat, level surfaces into more uneven ones. Published studies have described a variety of such shoes—all having a somewhat rounded bottom and a cut heel region or a cut forefoot region, or both (double rocker). Despite the fundamentally similar shoe geometries, the reported effects of rocker bottom shoes on gait biomechanics have varied considerably. Ten healthy subjects agreed to participate in the present study and were given appropriately sized Masai Barefoot Technology (St. Louis, MO), Skechers™ (Manhattan Beach, CA), and New Balance (Boston, MA) conventional walking shoes. After a 12-day accommodation period, the subjects walked wearing each shoe while 3-dimensional motion and force data were collected in the gait laboratory. The key findings included (1) increased trunk flexion, decreased ankle plantarflexion range, and reduced plantarflexion moment in the early stance; (2) increased ankle dorsiflexion and knee flexor moment in the midstance; (3) decreased peak ankle plantarflexion in the late stance; and (4) decreased ankle plantarflexion and decreased hip flexor and knee extensor moments in the pre-swing and into swing phase. The walking speed was unconstrained and was maintained across all shoe types. A biomechanical explanation is suggested for the observed changes. Suggestions for cautions are provided for using rocker bottom shoes in patients with neuromuscular insufficiency.

Free Functional Gracilis Muscle Transplantation for Reconstruction of Active Elbow Flexion in Posttraumatic Brachial Plexus Lesions

Reconstruction of powerful active elbow flexion. Reconstruction of missing muscle unit by neurovascular pedicled functional muscle transplantation. Treatment of last choice for --secondary reconstruction of active elbow flexion in case of complete lesion of the brachial plexus or musculocutaneous nerve (M0 muscle function = replacement indication), partial but incomplete lesion of the brachial plexus or musculocutaneous nerve (M1-(3) muscle function = augmentation indication); --replacement of the elbow flexor muscles in case of primary muscle loss (tumor, trauma). Concomitant lesions of the axillary artery. No adequate donor nerve. Relative: no sensibility at all at the forearm and hand. Free functional biarticular myocutaneous transplantation of gracilis muscle. A myocutaneous gracilis flap is raised at the thigh. At the upper arm the flap is fixed proximally to the coracoid process or the lateral clavicle. The distal insertion is sutured to the distal biceps tendon. Vascular anastomoses are carried out in end-to-side fashion with the brachial artery and vein. Nerval coaptation is done in end-to-end technique using the muculocutaneous nerve. Complete immobilization for 6 weeks. Dorsal upper arm splint until sufficient muscle power (M(4)). Progressive increase of active range of motion for another 6 weeks. Continuation of physiotherapy for 12-18 months. Postoperative standardized compression therapy, combined with scar therapy (silicone sheet). Functionally useful results can be expected in 60-75% of patients, especially if there is some residual function (M1 or M2) left ("augmentation indication"). Early free functional muscle transplantation shows best results in patients with direct muscle defect, because all vascular and neuronal structures are still available, and no secondary changes such as fibrosis or joint stiffness are present yet. There are inconsistent results for patients with neurologic insufficiency (i.e., total brachial plexus palsy) or mixed neuromuscular insufficiency, such as compartment syndrome. Especially in complete brachial plexus lesion, free functional muscle transfer is often the only treatment option. Provided there is a good patient selection, satisfactory results can be achieved for elbow flexion. Whether a higher number of axons, as provided by the contralateral C7 transfer, will lead to better results is the topic of an ongoing study.

Risk of Extubation Failure in Patients With Myasthenic Crisis

Weaning patients with myasthenic crisis (MC) from mechanical ventilation is often difficult, and the ideal time for extubation is often uncertain. However, little is known about the risk of extubation failure and the factors that may affect its occurrence. The goals of this study were to assess the risk of extubation failure in patients with MC and to determine which clinical variables may predict unsuccessful extubation. Retrospective review of consecutive patients admitted for MC. Weaning method was categorized as T-piece or continuous positive airway pressure (i.e., T-piece trials not performed). Extubation failure was defined as need for reintubation or tracheostomy due to persistent neuromuscular insufficiency. Functional outcome was assessed using the modified Rankin score. We identified 26 episodes of MC in 20 patients. Median age was 42.1 years (range 14-83 years). Most patients were treated with immunomodulatory therapy (73%). There were seven episodes of extubation failure (prevalence rate 27%). Median time to reintubation was 36 hours. Older age (p = 0.05), atelectasis (p < 0.01), and pneumonia (p =0.02) were significantly associated with extubation failure. Patients with failed extubation had considerably prolonged intensive care unit stays (median 28 versus 7 days; p < 0.01) and hospital stays (median 40 versus 12 days; p < 0.01). Extubation failure may often complicate MC. Older age and development of pulmonary complications during mechanical ventilation increase the risk of extubation failure.

Muscle biopsy investigations on neuromuscular insufficiency of the rotator cuff: a contribution to the functional impingement of the shoulder joint

The possibility that functional impingement results from muscular imbalance has been discussed. This study investigates whether disturbance of muscular coordination is reflected in a shift in the balance of fast-twitch and slow-twitch fibers, as fast-twitch fibers enable a rapid reaction or contraction and slow-twitch fibers enable slow contractions and sustained performance. The supraspinatus and deltoid muscles in 37 patients with a supraspinatus syndrome and partial or complete rupture of the rotator cuff underwent biopsy. All three groups of patients showed a reduction in size, increased variability, and change in the frequency distribution of fiber cross sections. The fast-twitch fibers were especially affected. These findings were confirmed objectively by morphometric measurements. It might be concluded from the changes mentioned above that disturbance in coordination of the musculature can cause a functional impingement. We term this neuromuscular insufficiency of the rotator cuff. The mechanical factors relating to subacromial impingement may only have a role in promoting its manifestation by restricting the compensatory range of the joint.

Neuromuscular failure of the rotator cuff as a contribution to the functional impingement of the shoulder - a muscle biopsy investigation

The possibility that functional impingement results from muscular imbalance is under discussion. This study investigates whether the disturbance of muscular coordination could be demonstrated as a shift in the balance of FT and ST fibers, since the FT fibers enable a rapid reaction or contraction, and ST fibers enable slow contractions and sustained performance. In 37 patients with a supraspinatus syndrome, partial or complete rupture of the rotator cuff, we took biopsies from the supraspinatus and deltoid muscles and did morphometric measurements.< All three groups of patients showed a reduction in size, increased variability and change in frequency of the fiber cross sections. The FT fibers are especially affected. These findings are objectively confirmed by morphometric measurements. A disturbance in coordination of the musculature which can bring about functional impingement might be inferred from the above changes. We term this "neuromuscular insufficiency of the rotator cuff". The mechanical factors relating to subacromial impingement probably only have a role in promoting its manifestation by restricting the compensation range of the joint.

Allocation of intensive care resources.

Since its inception some three decades ago the concept of intensive care underwent considerable changes: Firstly, the ICU has become a distinct hospital ward specifically built to allow the use of ultramodern technology and the execution of exhaustive protocols (infection control etc). Secondly, the patients admitted for therapy have evolved away from those suffering from the acute respiratory failure of neuromuscular insufficiency to encompass all clinical conditions representing a threat to life. Admission criteria have also changed and now include patients with poor or even no prognosis; the availability of an empty ICU bed often prompts the admission of a patient not requiring intensive care at all. Thirdly, costs have escalated enormously, second only to the operating suite as the most expensive clinical facility of the modern hospital. It is now estimated that as much as 20% of hospital resources are expended in the provision of ICU facilities for only 5% of total hospital admissions. Moreover, with an average rate of ICU mortality far exceeding 20%, a substantial sum of money is being invested to produce just one survivor.

Hypocalcemia in critically ill patients

To review calcium regulation, causes of hypocalcemia during critical illness, clinical features and treatment of hypocalcemia, hemodynamic effects of calcium administration, calcium-catecholamine interactions, and the role of calcium in ischemic injury. Representative articles from the medical literature are used to support the discussion of selected aspects of calcium metabolism which are important to the practice of critical care medicine. Results from both animal and human investigations and both in vitro and in vivo studies are discussed. Circulating calcium levels are best measured using ionized calcium electrodes. Ionized hypocalcemia is common in critically ill patients and usually results from impaired parathyroid hormone secretion or action, impaired vitamin D synthesis or action, or calcium chelation/precipitation. Ionized hypocalcemia most commonly presents as cardiovascular or neuromuscular insufficiency. Mild ionized hypocalcemia (greater than 0.8 mmol/L) is usually asymptomatic and frequently does not require treatment. Moderate-to-severe ionized hypocalcemia is best treated with iv calcium in the critically ill patient. The majority of studies report no increase in cardiac output but a significant increase in BP after iv calcium administration. When administered with beta-adrenergic agonists, calcium frequently impairs their cardiovascular actions. Intracellular calcium dysregulation is common during ischemic and shock states. Agents which increase intracellular calcium may be harmful during cellular ischemia. Alterations in calcium regulation and calcium concentrations are common during critical illness. Optimal management of altered calcium concentrations requires an understanding of the pathophysiology behind these alterations.