Morphometric analysis of the human cervical motoneurons in the aging process

Adverse postoperative outcomes in elderly patients with sarcopenia

PURPOSE

No study has compared 30-day and 90-day adverse postoperative outcomes between old-age patients with and those without sarcopenia.

PATIENTS AND METHODS

We categorize elderly patients receiving major surgery into two groups according to the presence or absence of preoperative sarcopenia that were matched at a 1:4 ratio through propensity score matching (PSM). We analyzed 30-day or 90-day adverse postoperative outcomes and mortality in patients with and without sarcopenia receiving major surgery.

RESULTS

Multivariate logistic regression analyses revealed that the patients with preoperative sarcopenia were at significantly higher risk of 30-day postoperative mortality (adjusted odds ratio [aOR]. = 1.25; 95% confidence interval [CI]. = 1.03-1.52) and 30-day major complications such as postoperative pneumonia (aOR = 1.15; 95% CI = 1.00-1.40), postoperative bleeding (aOR = 2.18; 95% CI = 1.04-4.57), septicemia (aOR = 1.31; 95% CI = 1.03-1.66), and overall complications (aOR = 1.13; 95% CI = 1.00-1.46). In addition, surgical patients with sarcopenia were at significantly higher risk of 90-day postoperative mortality (aOR = 1.50; 95% CI = 1.29-1.74) and 90-day major complications such as pneumonia (aOR = 1.27; 95% CI = 1.10-1.47), postoperative bleeding (aOR = 1.90; 95% CI = 1.04-3.48), septicemia (aOR = 1.52; 95% CI = 1.28-1.82), and overall complications (aOR = 1.24; 95% CI = 1.08-1.42).

CONCLUSIONS

Sarcopenia is an independent risk factor for 30-day and 90-day adverse postoperative outcomes such as pneumonia, postoperative bleeding, and septicemia and increases 30-day and 90-day postoperative mortality among patients receiving major surgery. No study has compared 30-day and 90-day adverse postoperative outcomes between patients with and those without sarcopenia. We conducted a propensity score?matched (PSM) population-based cohort study to investigate the adverse postoperative outcomes and mortality in patients undergoing major elective surgery with preoperative sarcopenia versus those without preoperative sarcopenia. We demonstrated that sarcopenia is an independent risk factor for 30-day and 90-day adverse postoperative outcomes, such as postoperative pneumonia, bleeding, septicemia, and mortality after major surgery. Therefore, surgeons and anesthesiologists should attempt to correct preoperative sarcopenia, swallowing function, and respiratory muscle training before elective surgery to reduce postoperative complications that contribute to the decrease in surgical mortality.

Impact of sarcopenia in trauma and surgical patient population: A literature review

Sarcopenia refers to the progressive and generalised loss of skeletal muscle mass and strength with a risk of adverse outcomes such as physical disability, poor quality of life and mortality. The present review explored the impact, diagnosis, prevention and management of sarcopenia in surgical and trauma patients. Recent evidence suggests that there are many factors contributing to its development other than age. Pathophysiology of sarcopenia is complex which makes its diagnosis difficult and there is no universal approach. It is a predictor of poor outcomes including post-operative complications, length of hospital stay and mortality in trauma and surgery patients. Sedentary lifestyle, age-dependent hormone and cytokine imbalance, decreased protein synthesis and regeneration, and motor unit remodelling are some of the main risk factors for sarcopenia. Dual energy X-ray absorptiometry, bio-electrical impedance analysis and computed tomography are frequently utilized for its diagnosis. Management of sarcopenia involves appropriate management of comorbidities, interventions to facilitate physical activities, nutrition interventions and pharmacotherapy.

Morphometric evaluations of the human nervous system

It is very important to evaluate and accurately understand the various conditions of the human nervous system. In this review article, we introduce several morphometric reports that are proven to be accurate from the view point of various errors (range of tissue shrinkage ratios, microscopic multiple counting, artifacts of microscopic structures, etc.). We review the following aspects of the selected reports: methodology, developmental research, neuronal differences, gender differences, aging process and miscellaneous (nerve fibers, unmyelinated fibers, in relation to neuropathology, clinical image-analysis and immunohistochemistry).

Morphometric comparison of human nerve cells: pyramidal motor system

We compared morphological and morphometric data on various motor neurons in the human pyramidal system using the modified Klüver-Barrera staining method with extremely minimized shrinkage ratio and an image-analyzer. We classified motor neurons in the human pyramidal system into three groups according to the measurement data. This report may be of interest to better understand the process of nerve conduction in the human pyramidal system.

Morphological characteristics of nerve cells in the human general sensory system

We conducted a study to compare morphological characteristics of various nerve cells in the sensory system. This sort of evaluation is indispensable for a better understanding of the nervous system in relation to clinical physiology and neurology.

Morphometric comparison of human spinal cord anterior horn cells between the cervical and lumbar levels

Morphometric comparisons of anterior horn cells (AHCs) were conducted between cervical and lumbar spinal cords in 29 cadavers. The sizes of the AHCs were always larger at the lumbar level than at cervical level irrespective of the age of the spicemens, but a decrease in size with age was observed at both levels. The correlation coefficient shows a larger decrease in numbers and volumes at lumbar level than at cervical level.

Effects of aging on muscle fibre type and size

Aging has been associated with a loss of muscle mass that is referred to as 'sarcopenia'. This decrease in muscle tissue begins around the age of 50 years, but becomes more dramatic beyond the 60th year of life. Loss of muscle mass among the aged directly results in diminished muscle function. Decreased strength and power contribute to the high incidence of accidental falls observed among the elderly and can compromise quality of life. Moreover, sarcopenia has been linked to several chronic afflictions that are common among the aged, including osteoporosis, insulin resistance and arthritis. Loss of muscle fibre number is the principal cause of sarcopenia, although fibre atrophy--particularly among type II fibres--is also involved. Several physiological mechanisms have been implicated in the development of sarcopenia. Denervation results in the loss of motor units and thus, muscle fibres. A decrease in the production of anabolic hormones such as testosterone, growth hormone and insulin-like growth factor-1 impairs the capacity of skeletal muscle to incorporate amino acids and synthesise proteins. An increase in the release of catabolic agents, specifically interleukin-6, amplifies the rate of muscle wasting among the elderly. Given the demographic trends evident in most western societies, i.e. increased number of those considered aged, management interventions for sarcopenia must become a major goal of the healthcare profession.

Morphometric analyses of axons in the human lateral corticospinal tract: cervical/lumbar level comparison and relation to the ageing process

Myelinated axons in the human lateral corticospinal tract (LCST) at the C6 and L4 levels were examined on 16 male cadavers, with age ranging from 41 to 88 years. The average area of axons in the LCST was measured using a microscopic image-analyzing system. Our data show that the average area of axons at the C6 and L4 levels decreased with age. We also noticed that the average area of axons was larger at the C6 level than at the L4 level in all cases. This decrease may be related to a parallel decrease of conduction velocity in the LCST during the ageing process.

Life-long stability of neurons: a century of research on neurogenesis, neuronal death and neuron quantification in adult CNS

In this chapter we provide an extensive review of 100 years of research on the stability of neurons in the mammalian brain, with special emphasis on humans. Although Cajal formulated the Neuronal Doctrine, he was wrong in his beliefs that adult neurogenesis did not occur and adult neurons are dying throughout life. These two beliefs became accepted "common knowledge" and have shaped much of neuroscience research and provided much of the basis for clinical treatment of age-related brain diseases. In this review, we consider adult neurogenesis from a historical and evolutionary perspective. It is concluded, that while adult neurogenesis is a factor in the dynamics of the dentate gyrus and olfactory bulb, it is probably not a major factor during the life-span in most brain areas. Likewise, the acceptance of neuronal death as an explanation for normal age-related senility is challenged with evidence collected over the last fifty years. Much of the problem in changing this common belief of dying neurons was the inadequacies of neuronal counting methods. In this review we discuss in detail implications of recent improvements in neuronal quantification. We conclude: First, age-related neuronal atrophy is the major factor in functional deterioration of existing neurons and could be slowed down, or even reversed by various pharmacological interventions. Second, in most cases neuronal degeneration during aging is a pathology that in principle may be avoided. Third, loss of myelin and of the white matter is more frequent and important than the limited neuronal death in normal aging.