千田 益生

Forty-one hands of 37 patients with idiopathic carpal tunnel syndrome treated by endoscopic carpal tunnel release (ECTR) were followed up for more than one year after surgery. Surgical results were evaluated using Kelly's criteria, the Semmes-Weinstein test, the static and moving 2-point discrimination tests, tip-pinch strength, and motor and sensory nerve conduction studies. Clinical results, according to Kelly's criteria three months after surgery, were excellent or good in 36 hands, and fair or poor in five hands. No recovery was evident at six months and 12 months after surgery in fair and poor hands. Based on these findings, we conclude that a neurolysis of the median nerve and release of constriction of the thenar muscle branch should be performed using the conventional open technique for patients with poor results three months after ECTR if the patients are dissatisfied with ECTR results

The purposes of this study were to examine whether body sway is altered immediately after strabismus surgery in children and to find preoperative clinical factors associated with body sway. In a prospective study, body sway was measured on 1-3 days before surgery and on the third day after surgery; for the measurements, computerized static stabilometry was carried out on 28 consecutive patients with strabismus (age range: 3 to 12 years old; mean: 7.4) who underwent strabismus surgery under general anesthesia. The linear length of the sway path (cm), the linear length of the sway path in a particular unit of time (cm/second), and the area of the sway path (cm2), indicative of the extent of body sway, all increased significantly among a total of 28 patients in both conditions of the patient's eyes open and closed, as well as among those in a subgroup of 16 patients with exotropia, after they had undergone strabismus surgery (p < 0.05, Wilcoxon signed ranks test). The center of pressure along the Y axis of orientation from the toe to the heel was found to deviate significantly toward the heel postoperatively, as compared with the preoperative center in the subgroup of 16 patients with exotropia (p < 0.05). Before surgery, 15 patients with no stereoacuity exhibited a greater amount of body sway when their eyes were open than did 13 patients with measurable stereoacuity (p < 0.05, Mann-Whitney U-test). In the subgroup of 16 patients with exotropia when their eyes open, 3 patients with abnormal head posture exhibited more extensive body sway than did 13 patients without abnormal head posture (p < 0.05). Body sway was found to significantly increase immediately after strabismus surgery in children with strabismus. Stereoacuity and abnormal head posture are 2 clinical factors associated with preoperative postural instability.

We observed differences in the capillary architecture of the skeletal muscles that have different fiber metabolism. The soleus, the vastus intermedius and the tibialis anterior muscles of adult Wistar rats were prepared using two different techniques. Samples for adenosine triphosphatase (ATPase) staining were prepared following Dubovitz's method, and the distributions of fiber type, Types 1, 2A and 2B, were analyzed. Then, corrosion casts of capillary architecture of these muscles prepared following Murakami's method were observed with a scanning electron microscope (SEM) and compared with the fiber distribution. The fiber type composition of the soleus muscle showed Type 1 (slow-twitch) dominance and that of the vastus intermedius and the tibialis anterior muscle showed Type 2 (fast-twitch) dominance. The capillaries of the soleus muscle were tortuous, and this was thought to be advantageous for blood supply. In contrast, the capillaries of the vastus intermedius and tibialis anterior muscles had a relatively parallel pattern. Additionally, two different patterns of capillary architecture that appeared to correspond to certain metabolic characteristic of different muscle fiber types were preserved with corrosion casting. In conclusion, comparative studies on capillary architecture of the skeletal muscles are useful for analyses of its function.

We studied the magnetic resonance imaging (MRI) of 120 knees in 86 rheumatoid arthritis (RA) patients and of 14 unaffected knees in 12 control cases. We also developed a scoring system as a quantitative analysis method. We divided the MRI into 10 items, and classified the severity of the symptoms into 4 grades (score 0 to 3). The average total score increased according to the radiographic grade. Soft tissue lesions were clearly detected, even in the early stages of RA. Items such as synovial proliferation showed a high score even in the early stages, suggesting that it was the initial symptom of RA. The score also showed a correlation with the inflammatory signs. These results suggest that this scoring system is very sensitive and yields a good reflection of RA activity. We demonstrated that this system is simple and convenient for routine diagnostic use. We further demonstrated that it is useful for following the advancement of RA and for evaluating the response to treatment.

We investigated the degree of local heat and swelling of the thigh muscles produced by exercise. Eleven university athletes aged from 19 to 23 years old performed isokinetic exercise of the right knee on a Cybex II. Then serial determination of thigh circumference and thigh temperature (up to 120 min after exercise) as well as serial magnetic resonance (MR) imaging (up to 60 min after exercise) was performed on both thighs. The circumference of the right thigh peaked at 5.6 +/- 2.1 min after exercise and returned to normal at 38.6 +/- 9.2 min. The temperature of the right thigh peaked at 14.2 +/- 5.7 min after exercise and was not normalized after 120 min except in two subjects. T2-weighted MR images showed a marked increase in the signal intensity of the right knee flexor and extensor muscles. The signal intensity peaked immediately after exercise and subsequently decreased gradually but did not return to normal after 60 min in some muscles. Changes in the thigh circumference were closely correlated with changes in the MR findings. The changes in the thigh muscles after knee exercise could be demonstrated using MR imaging, thigh circumference, and thigh temperature data. These parameters may provide indicators for managing muscle fatigue and recovery.

The influence of mild exercise on skeletal muscle fibers was investigated histochemically to assess the effects of exercise on steroid myopathy and its efficacy for preventing this disease. Twenty male Wistar rats were divided into 4 groups of 5 each: group T, which received exercise alone; group S which received steroid alone; group ST which received both exercise and steroid; and group C, the control group. In groups S and ST, hydrocortisone was administered subcutaneously at a dose of 10 mg/kg/day for 4 weeks. In the exercise groups, the animals were made to run at a speed of 15 m/min for about 1 h/day for 5 days a week on a treadmill. After the completion of treadmill exercise and steroid administration for 4 weeks, the rats were anesthetized with Nembutal, the soleus muscle (SOL) and the extensor digitorum longus muscle (EDL) were removed and prepared for examinations. The area of type I fibers in the SOL was significantly larger in group ST than in group S. The area of type IIa fibers in the EDL was significantly larger in group ST than in group S. In group S, the proportion of type I fibers in the SOL was significantly lower than in the other three groups. There was little difference in fiber type distribution between groups ST and C. These results suggest that steroid myopathy can be prevented by even mild exercise.

Lumbar X-ray findings and clinical manifestations were investigated in 10 patients who underwent posterior fusion with or without Harrington instrumentation for idiopathic scoliosis between 1965 and 1975. The subjects were 4 men and 6 women, who ranged from 10 to 17 years of age at the time of surgery (mean, 12 years and 9 months). The postoperative follow-up period ranged from 20 to 30 years (mean, 24 years and 7 months). All patients were followed-up at our institution. Three patients received posterior fusion without instrumentation, and Harrington instrumentation was used in 7 from 1967 onwards. The distal end of the fusion was L2 in 4, L3 in 4, and L4 in 2 patients. Pain, evaluated by Moskowitz's criteria, was stage 1 in 5 and stage II in 5 patients (none of them had stage III or IV). In X-ray evaluation, graded according to Lawrence's classification, grade III changes were noted in 2 patients; one with thoracolumbar fusion with Harrington instrumentation to the L4 vertebra and the other patient was assessed at 30 years post-surgery. According to White-Panjabi's criteria, instability was noted in 1 patient with Harrington fixation including the L4 vertebra. Clinical manifestations and X-ray abnormalities were less severe than anticipated at 20 years plus post-surgery, although a tendency for deterioration was observed in patients with fusion including the L4 or patients followed up for more than 30 years post-surgery.

In order to examine fatigue of the knee flexor and extensor muscles and to investigate the characteristics of muscular fatigue in different sports, a Cybex machine was used to measure muscle fatigue and recovery during isokinetic knee flexion and extension. Eighteen baseball players, 12 soccer players and 13 marathon runners were studied. Each subject was tested in the sitting position and made to perform 50 consecutive right knee bends and stretches at maximum strength. This was done 3 times with an interval of 10 min between each series. The peak torque to body weight ratio and the fatigue rate were determined in each case. In all subjects, the peak torque to body weight ratio was higher for extensors than flexors. Over the 3 trials, the fatigue rate of extensors showed little change, while that of flexors had a tendency to increase. In each subject, knee extensors showed a high fatigue rate but a quick recovery, while knee flexors showed a low fatigue rate but a slow recovery. As the marathon runners had the smallest fatigue rates for both flexors and extensors, we concluded that marathon runners had more stamina than baseball players and soccer players.

The aim of this study was to investigate the relationship between the strength of the foot muscles that control the toes and disorders such as shin splint. In order to this, we designed and built a toe dynamometer to compare the muscle power exerted through the toes in top female marathon runners and age-matched women not involved in sports. The subjects were 12 top-level female marathon runners (Group A) and 37 student nurses who were not involved in sports (Group B). We devised a dynamometer to measure the total power exerted by the flexor muscles of the 5 toes of a single foot (total flexor power) and the combined power of the abductors of the big (1st) and little (5th) toes (abductor power). In Group A, the total flexor power was 14.3 +/- 5.3 kg in the right foot and 15.4 +/- 4.7 kg in the left foot. The abductor power was 1.9 +/- 1.8 kg in the right foot and 2.2 +/- 1.9 kg in the left foot. In Group B, total flexor power was 18.3 +/- 6.7 kg in the right foot, while the abductor power was 1.9 +/- 1.7 kg. The subjects from Group A with an arch index < 1.0 (n = 8) or > 1.0 (n = 4) were respectively classified as Group I and Group II. In Group I, total flexor power was 14.9 +/- 5.3 kg (right) and 15.5 +/- 5.2 kg (left), while the abductor power was 2.6 +/- 1.9 kg (right), and 3.1 +/- 1.7 kg (left). In Group II, the total flexor power was 13.2 +/- 5.8 kg (right) and 15.1 +/- 4.2 kg (left), while the abductor power was 0.7 +/- 0.6 kg (right) and 0.3 +/- 0.2 kg (left). The abductor power of toes was significantly lower in Group II than in Group I. The incidence of posteromedial shin pain was higher in Group II (75.0%) than in Group I (12.5%).

To study the pathology of muscle atrophy in rheumatoid arthritis (RA), we examined the vastus medialis in rheumatoid patients histologically. The relationship of the findings to their ambulatory ability and long-term steroid therapy was investigated. The muscles of the RA patients were also compared with those of patients with osteoarthritis (OA). Specimens of the vastus medialis were collected from 29 knees of 23 patients with RA and 16 knees of 13 patients with OA during total knee arthroplasty. Muscle fibers were classified according to their type, and the ratio between the area of single type I and type II fibers as well as the ratio between the total area of these fibers was calculated. The total area of type II fibers in the RA group was significantly greater than in the OA group (P < 0.05). In the RA group, the mean proportion of the type II fibers relative to the total muscle fiber area tended to increase with the decline of ambulatory ability, while there was no such increase in the OA group. The proportion of type II fibers was increased significantly in RA patients on long-term steroid therapy when compared to those without therapy. In the ratio of the area of a single fiber, there was no clear relationship to ambulatory ability and long-term steroid therapy. It is considered that muscle atrophy in RA is not solely disuse atrophy, but also has a close relationship to steroid therapy and the pathology of the disease itself.

Accurate assessment of elbow function is important to determine the total ability of the arm. The purpose of this study was to clarify the relationship between isometric muscle strength of the elbows of patients with rheumatoid arthritis (RA) and Larsen's X-ray evaluation. Fifty-six elbows of 45 RA patients aged 47 to 77 years (mean age, 63 years) were tested. Muscle strength was measured with an isometric torque-cell dynamometer. Test-retest reliability of the dynamometer was proven by measuring 12 elbows of 6 healthy young men. In RA patients, elbow flexion and extension strength decreased in proportion to increases in the severity of Larsen's grades from Grade 1 to 4. However, Grade 5 elbows had greater muscle strength than those in Grade 4. Forearm pronation and supination strength also decreased in proportion to increases in the severity of Larsen's grades from Grade 1 to 5. This quantitative study made it clear that the muscle strength of RA patients' elbows almost completely correlates to X-ray finding according to the grade of Larsen's evaluation based on X-rays. With regard to muscle strength of postoperative elbows, both flexion strength and supination strength after total elbow replacement (TER) were about two times greater than before TER, and after synovectomy it was as great as those in non-operative RA patients of Grade 2.

Muscle power in the lower extremities and body sway were measured in 57 healthy young women volunteers in their 20's. Body sway was measured with a stabilimeter for 30 sec during two-leg standing, and for 10 sec during one-leg standing with the eyes open or closed, alternating between right and left legs (5 times each). The measured parameters of body sway were locus length per time unit, locus length per environmental area, environmental area, rectangle area, root mean square area, and the ratio of sway with eyes closed to sway with eyes open. Knee flexor and extensor power and toe flexor and abductor power were the measures representing lower extremity muscle power. The increase in sway with the eyes closed was more marked during one-leg standing than two-leg standing, as expected. We found that 36 of 57 subjects (62%) were unable to maintain one-leg standing with their eyes closed, and this failure correlated with marked body sway (P = 0.0086). Many subjects had one leg that was classified as stable and the other leg classified as unstable. Clearly, testing of both legs alternately with eyes closed is necessary to measure the full range of sway in subjects. Lower extremity muscle power did not appear to be the dominant factor in maintaining balance in these young subjects.

Conservative treatment is ineffective for ossification of the posterior longitudinal ligament (OPLL) in the thoracic spine, and surgical treatment is indicated for most cases, while such cases are not often experienced. In the present study, the results of surgical management involving mainly posterior decompression for this disease were evaluated clinically. The study included 9 patients (1 man and 8 women) who underwent surgical treatment for OPLL of the thoracic spine between 1984 and 1993. Laminectomy was performed in 5 patients, and laminectomy plus anterior decompression of the OPLL via the posterior approach based on Otsuka's method was performed in 2 patients. In 1 patient, laminoplasty for OPLL of the cervical spine was combined with laminectomy of the symptomatic lesion in the thoracic spine. One patient underwent anterior decompression and fusion. The results were evaluated using the Japanese Orthopaedic Association score (JOA score) and recovery rate. The postoperative follow-up period ranged from 1 year to 10 years and 3 months (mean, 4 years and 6 months). The mean JOA score was 4.8 before surgery and improved to 7.6 at the final examination. This was a mean recovery rate of 50.1%. Symptoms caused by OPLL in the thoracic spine can be alleviated by posterior decompression where OPLL extends from the upper to the middle thoracic spine or extends from the middle to the lower thoracic spine. It seems, however, that OPLL localized to the middle thoracic spine requires anterior decompression.