Osamu Shirado

Lumbar Trunk Muscle Endurance Testing: An Inexpensive Alternative to a Machine for Evaluation

OBJECTIVES The goals of this study were to verify the reliability and safety of new methods for evaluating trunk muscle endurance, and to compare the differences between healthy subjects and patients with chronic low-back pain. DESIGN Randomized and controlled study. SETTING A referral center and institutional practice, and outpatient care. SUBJECTS Ninety healthy subjects (37 men and 53 women average age 46.2 years) and 100 patients with CLBP (40 men and 60 women; average age 45.3 years) participated in this study. MAIN OUTCOME MEASURES During trunk flexor and extensor endurance tests, the subjects were asked to maintain the original positions for as long as possible. The performance time (seconds) for which subject could maintain the position was compared between two groups. Test-retest correlation (r) was also analyzed. The degree of lumbar lordosis was compared in conventional and new methods. RESULTS All test-retest correlations were significantly high in both groups (p < .01). The performance time was much longer in the healthy subjects than in the patients with CLBP during any procedures (p < .01). Lumbar lordosis was significantly less in our method than in the Kraus-Weber test (p < .01). CONCLUSIONS This study demonstrated that our methods for measuring trunk flexor and extensor endurance had high reliability, reproducibility, and safety, and were easy to perform, with no need for special equipment. This study also showed that trunk muscles in patients with CLBP were more easily fatigued, compared with those in healthy subjects.

Influence of disc degeneration on mechanism of thoracolumbar burst fractures.

In order to clarify the pathomechanism of thoracolumbar burst fractures and to evaluate the influence of disc degeneration and bone mineral density, a biomechanical study was performed using cadaveric spines. Eleven motion segments of thoracolumbar spines from human cadavers were compressed vertically until a fracture occurred. In addition, bone mineral density and degree of disc degeneration were determined for each specimen. Compression of 7 of 11 specimens resulted in the typical burst fracture characterized by retropulsion of a bony fragment into the spinal canal and an increase of the interpedicular distance. All seven specimens showed disruptions of the middle end plate and disc materials in the vertebral body. The fracture line was located between the middle of the end plate and the middle of the posterior wall cortex. No burst fractures were seen in the specimens with severely degenerated discs and osteoporosis. In order to confirm the stress state in a vertebra that induces the burst fracture, finite element analysis of one motion segment was also carried out under the same mechanical conditions as the experiments in this study. As a result of calculation for the healthy disc, the highest stresses under axial compression were concentrated in the following areas: the middle of the end plate, the cancellous bone under the nucleus pulposus, and the middle of the posterior wall cortex. This implies that the above regions are more vulnerable to vertical compressive load. In the analysis of specimens with severely degenerated discs, stresses were very low at the end plate and cancellous bone under the nucleus. Therefore, axial compression was reconfirmed as inducing typical burst fractures in the thoracolumbar spine. Moreover, the mechanism of this fracture was influenced by disc degeneration and bone mineral density.

Trunk-muscle strength during concentric and eccentric contraction: a comparison between healthy subjects and patients with chronic low-back pain

The physical evaluation and exercise program of trunk muscles in patients with chronic low-back pain (CLBP) is still controversial. Many studies have been performed in the isometric and/or concentric contraction mode. Few data, however, have been reported on trunk-muscle strength during eccentric contraction, which plays a significant role in functional activities. To evaluate whether trunk-muscle strength on eccentric contraction could be applicable to the assessment and exercise of the patients with CLBP, trunk strength was measured in 20 healthy men and 16 healthy women, as well as 15 male and 10 female patients with CLBP. Maximum voluntary concentric and eccentric strength was measured during attempted flexion and extension in a seated position. In the healthy subjects, the maximum torque of extensors was greater than that of the flexors during both concentric and eccentric contraction (p less than 0.05). In flexors and extensors, maximum torque exerted on the eccentric contraction was always greater than that on the concentric contraction (p less than 0.05). Although strength was likely to be weaker in the patients with CLBP than in the healthy subjects, there were no statistical differences between the two groups. In terms of the flexor/extensor ratio of maximum torque, there were also no statistical significances between the two groups in either contraction mode. In the flexors, correlation coefficient (r) between concentric and eccentric torque was 0.84 for the healthy subjects and 0.48 for the CLBP subjects (p less than 0.05). In the extensors, the coefficient was 0.90 for the healthy patients and 0.71 for the CLBP patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Electromyographic Analysis of Four Techniques for Isometric Trunk Muscle Exercises

Posture to avoid hyperextension of the lumbar spine during isometric trunk muscle exercises has been widely recommended. However, there are no common standards for cervical and pelvic alignment during exercises. To investigate the effects of four different techniques regarding cervical and pelvic alignment, electromyographic (EMG) and radiological studies were performed on 30 healthy subjects. The four different postures were: (1) maximally extended neck, (2) neutral neck, (3) maximally flexed neck, and (4) maximally flexed neck with pelvic stabilization through muscle contraction. During flexion exercises, the largest increase in EMG activity in the abdominal muscles was observed with the flexed neck with pelvic stabilization (p < .01). During extensor exercises, the largest increase in EMG activity in the erector spinae was also obtained in the same position (p < .01). An increase of EMG activity in antagonist muscles (eg, erector spinae on flexion, and rectus and oblique muscles on extension) was also greatest with the flexed neck and pelvic stabilization. From the radiographic study, degrees of lumbar lordosis were least with the flexed neck and pelvic stabilization (p < .01). This study showed that neck and pelvic alignment can influence the EMG activity of trunk flexors and extensors during isometric trunk exercises. For isometric trunk muscle exercises, a maximum flexed neck with pelvic stabilization through muscle contraction seems to be the most optimal posture for decreasing the lumbar lordosis and for activating trunk flexors and extensors most effectively.

Quantitative histologic study of the influence of anterior spinal instrumentation and biodegradable polymer on lumbar interbody fusion after corpectomy. A canine model.

Histomorphometric and incroradiographic studies were performed to investigate whether there are different rates of bone remodeling based on the intrinsic stability with anterior spinal instrumentation and to evaluate if blodegradable polymer could be used clinically as the material of choice for anterior spinal instrumentation. Twenty-one coon hounds underwent anterior and posterior spinal destabilizing procedures to produce a reproducible amount of spinal instability: corpectomy of L5, disccetornies and partial facetectomies of L4–5 and L5–6, resections of L5 lamina, spinous process, supra-and interspinous ligament, and ligamentum flavum. Group 1 (N = 7) underwent anterior autogenous ulna strut graft alone at L4–6; group 2 (N = 7) underwent anterior biodegradable polyner strut alone at the same level; group 3 {N = 7) underwent same bone graft as in group 1, augmented by anterior Kaneda device, Six months after surgery quantitative histologic study showed that device-related osteopenia occurred in spines treated with Kaneda device. Within the L5 vertebral body the volumetric density of bone (mm3/cm3) was less for the group with Kaneda device (group 3) compared with that without instrumentation (group 1, P < 0,05). In the spine treated with biodegradable polymer, no advetsu host tissue responses were observed histologically. In addition, osteoconductive abilities of the polymer were suggested microscopically. Its mechanical property, however, was not rigid enough to stabilize the corpectomized spine.

Outdoor winter activities of spinal cord-injured patients : with special reference to outdoor mobility ?

Shirado O, Shundo M, Kaneda K, Strax TE: Outdoor winter activities of spinal cord-injured patients: with special reference to outdoor mobility. Am J Phys Med Rehabil 1995;74:408—414 Two hundred forty-seven patients with spinal cord injuries living in Hokkaido, the northern part of Japan, were mailed a questionnaire relating to winter outdoor activities. One hundred eight patients responded to the questionnaire, 98 males and 10 females, with ages ranging from 30 to 79 (mean, 53.3) yr. Injury levels of patients were: cervical in 23 patients, thoracic and thoracolumbar in 47, and lumbar in 38. All respondents were unable to walk independently because of quadriplegia or paraplegia. Approximately 90 percent of respondents found it necessary to go outside during the winter season. Eighty-five percent were outside during the coldest period. The most common reasons for outdoor activities were shopping and routine doctors appointments. The main method of ambulating outside was a manual and/or electrically operated wheelchair, sometimes in conjunction with an automobile. However, there were many problems reported in using wheelchairs; for example, wheels and casters were very slippery on the snow and ice, casters were easily buried in the snow, and wheelchair rims were very cold to handle. It was also pointed out that exposure to cold weather induced physical problems such as muscle spasticity, pain, and numbness of lower extremities. This survey revealed that spinal cord-injured patients would benefit from a wheelchair specifically designed for winter conditions.

Kinesiologic analysis of dynamic side-shift in patients with idiopathic scoliosis

OBJECTIVES The purpose of this study was to analyze the ability of the patients with idiopathic scoliosis to transfer the body weight in the frontal plane. DESIGN Randomized and controlled study. SETTING A referral center and institutional practice and outpatient care. SUBJECTS Fifty patients with idiopathic scoliosis (three men and forty-seven women; average age 15.3 years) and 15 normal women (average age 17.3 years) participated in this study. Thirty patients were treated with underarm braces. MAIN OUTCOME MEASURES Computer-assisted force plates were used to evaluate the laterally shifted weight and the time period during side-shift on sitting. RESULTS During both slow and fast side-shifts, shifted weight in the patients with idiopathic scoliosis was significantly less than in the normal controls (p < 0.05). The shifted weight was less on the concave side than on the convex one. The time for the shift to the concave side was longer in the patients than in the normal controls (p < 0.05). The brace was effective in correcting the imbalance of shifted weight in the patients with idiopathic scoliosis. CONCLUSIONS The current study demonstrated the different patterns of weight side-shift between normal subjects and patients with idiopathic scoliosis. The patients transferred less weight laterally than the normal subjects during slow and fast random movements. The patients also showed slower side-shift patterns than the normal subjects during the fast random movement.

Herniation of the Disc between the First and Second Lumbar Vertebrae with a Monoradiculopathy of the Fifth Lumbar Nerve Root. A Case Report

The clinical presentation of a herniated lumbar disc depends on which nerve root is affected. Therefore, the diagnosis of the level of herniation is initially based on the neurological symptoms and signs and is confirmed by a radiographic examination. Herniation of a disc at a level between the first and fourth lumbar vertebrae usually causes compression of the second, third, or fourth lumbar nerve roots. In addition, the herniation is associated with characteristic findings, including pain and sensory loss over the anterior portion of the thigh or the medial aspect of the leg, or both; a positive femoral-nerve-stretch test; weakness of the quadriceps or the iliopsoas muscle, or both; and a diminished or absent patellar ligament reflex3. Our report describes a patient who had a herniated disc between the first and second lumbar vertebrae with sciatica and a monoradiculopathy of the fifth lumbar nerve root. A sixty-seven-year-old woman was admitted to the hospital because of low-back pain, sciatica on the left, and weakness of the left lower extremity. For two months she had had low-back pain, and for three weeks pain had radiated from the left buttock to the lateral aspect of the thigh, the anterolateral portion of the leg, and the dorsal part of the foot. She had slight difficulty walking because of muscular weakness. She had no bowel or bladder incontinence. The pain was aggravated with movement of the trunk, especially forward bending, and was relieved by bed rest. The initial physical examination revealed diffuse tenderness over the low back and localized tenderness over the posterior portion of the left thigh and calf. A straight-leg-raising test was positive at 60 degrees on the left, and the femoral-nerve-stretch test was negative. No atrophy or fasciculation of the muscles was found. A neurological examination demonstrated weakness (grade 4 …

Lumbosacral fracture-subluxation associated with bilateral fractures of the first sacral pedicles: a case report and review of the literature.

A case of an unusual lumbosacral fracture-subluxation associated with bilateral fractures of the first sacral pedicles is described. The authors are aware of only one reported case in the literature. A 58-year-old man was involved in an accident during which his trunk was severely twisted toward the left and flexed. He also demonstrated L5 and S1 radiculopathies. He was successfully treated with surgical decompression of the L5 and S1 nerve roots with bilateral foraminotomies, followed by posterolateral arthrodesis at the lumbosacral junction using a transpedicular screw system that extended fixation into the ilia.

Elektromyografische analyse van vier technieken voor isometrische oefeningen ten behoeve van de rompmusculatuur

Chronische lage-rugpijn is een belangrijk socio-economisch probleem in geindustrialiseerde landen. Omdat het ontstaan van lage-rugpijn verband lijkt te houden met onvoldoende kracht van de rompmusculatuur, worden voor veel patienten met lage-rugpijn spierversterkende oefeningen voor de rompspieren voorgeschreven. De rompspieren worden meestal verdeeld in twee hoofdgroepen: de rompflexoren (buikspieren) en de rompextensoren (rugspieren).