State classification of heart rate variability by an artificial neural network in frequency domain.

This paper examines the feasibility of accurate state classification of autonomic nervous activity (ANA) based on the power spectral pattern of the heart rate fluctuations (HRFs). Some attempts have been made to utilize artificial neural networks (ANNs) to classify HRFs for clinical diagnoses such as ischemic cardiomyopathy, arrhythmia or sleep apnea. To establish the firm bases for making such clinical diagnoses, it may be important to examine the classification accuracy for the data in physiologically well defined conditions by e.g. application of autonomic blocking agents. In this paper the three layered perceptron has been trained by the heart rate data in variety of ANS states yielded by the application of Atropine and Propranolol to 14 healthy male subjects. Six state (control, atropine and propranolol for each of the spine and upright posture) classification based on power spectrum showed average sensitivity of 67.2% and specificity 91.2%. Four state (control, atropine, propranolol and double block for either spine or upright posture) resulted in the average classification sensitivity of 75.7% and specificity 95.5%. The paper revealed that entropy bandwidth and indices originated from characteristic oscillations of blood pressure change improve the classification accuracy.

Incidence of complications associated with spinal endoscopic surgery: nationwide survey in 2007 by the Committee on Spinal Endoscopic Surgical Skill Qualification of Japanese Orthopaedic Association.

BACKGROUND: This report was conducted to elucidate the current status of spinal endoscopic surgery and relevant incidents through analysis of the results of a questionnaire survey conducted in 2007 by the Committee on Spinal Endoscopic Surgical Skill Qualification of the Japanese Orthopaedic Association (JOA). METHODS: Questionnaire forms were sent to 2011 training facilities nationwide certified by the JOA, and 1082 of these facilities returned the filled questionnaires (response rate 53.8%). Of these facilities, 257 (23.8% of the responding facilities) undertook spinal endoscopic surgery in 2007. These institutions were asked to fill in the survey form with the details of the operations and relevant incidents as well as the incident levels. RESULTS: In total, the 257 facilities performed 6239 spinal endoscopic surgeries during 2007. Posterior spinal endoscopic surgery constituted most of the operations (6217 cases, 98.2%) including 4336 cases of microendoscopic discectomy (MED), 1273 cases of microendoscopic laminectomy or fenestration, and 379 cases of transforaminal or posterior lumbar interbody fusion. The total number of incidents was 133 (2.13%). The numbers of incidents by operative method were 75 (56.4%) during MED, 57 (42.9%) during microendoscopic laminectomy or fenestration, and 1 (0.8%) during interbody fusion. Of 133 incidents, dural tear occurred in 99 (74.4%), injury of the cauda equina or a nerve root in 7 (5.3%), facet fracture in 7 (5.3%), hematoma and wrong level in 6 each (4.5%), and wrong side and bedsore in 1 each (0.8%). The incident level was level 1 in 6, level 2 in 24, level 3a in 82, level 3b in 16, level 4 in 5, and level 5 (fatal) in 0. CONCLUSIONS: The results of this survey revealed an increasing trend of spinal endoscopic surgery and a decreasing trend of the complication rates. The complication rates of spinal endoscopic surgery were not higher than those of conventional surgery, indicating the safety of this surgical method.

Alendronate inhibits periprosthetic bone loss around uncemented femoral components.

Periprosthetic bone loss can be severe around the femoral component after uncemented arthroplasty. This study investigated the inhibitory effect of alendronate on periprosthetic bone loss. Seventeen patients underwent arthroplasty with an uncemented femoral component. Among them, 8 patients were given alendronate 5 mg once daily for 1 year (ALN group) and 9 patients received no pharmacotherapy (control group). Bone mineral density was measured in six periprosthetic zones by dual-energy X-ray absorptiometry at 1, 6, and 12 months after surgery. The average periprosthetic bone mineral density was 0.674-0.920 g/cm(2) at 1 month after surgery. From 6 months onward, the absolute bone mineral density and the ratio relative to the 1-month value were significantly decreased in the proximal zones of the femur in the control group (the ratio decreased from 0.817 to 0.769; P = 0.0040-0.0353). In the ALN group, however, the absolute and relative bone mineral density of the proximal femur remained unchanged for 12 months. In the other femoral zones, the absolute and relative bone mineral density remained unchanged throughout the study in both groups. We concluded that alendronate significantly inhibited the decrease of periprosthetic bone mineral density in the proximal femur after uncemented arthroplasty.