Prolactin and cortisol in cerebrospinal fluid: sex-related associations with clinical and psychological characteristics of patients with low back pain.

Clinical and psychological characteristics of 33 patients with low back pain were correlated with prolactin and cortisol concentrations in cerebrospinal fluid (CSF). A significant sex difference was found in CSF prolactin levels: women secreted more prolactin into the CSF than did men. High CSF cortisol levels were associated with a rhizographically-demonstrable abnormality, suggesting a relationship between cortisol and an 'organic' origin of pain symptoms. Impairment-disability indices also were associated with CSF hormone levels. Moreover, the two hormones had dissociated psychological correlates. Prolactin was related to depression and anxiety, whereas cortisol was related to somatization. Sex differences were observed in the cortisol response to the symptoms of chronic low back pain, especially in the presence of anxiety and somatization. The sex differences in psychoneuroendocrine and emotional responses suggest that male and female pain patients have different coping mechanisms.

Traumatic spinal cord injury as a complication to ankylosing spondylitis. An extended report.

OBJECTIVE: Käpylä Rehabilitation Centre is in Finland the only unit taking care of the subacute rehabilitation activities of patients with spinal cord injury (SCI). The annual incidence of new patients with SCI is 55 (1.1 per 100,000 inhabitants). The ankylosed spine (AS) is reported to be at greater risk for fracture and SCI. The aim of the study was to clarify if this higher risk of ankylosing spondylitis (AS) could also be detected among patients with traumatic SCI rehabilitated at Käpylä Rehabilitation Centre. Further, the aim was to evaluate the characteristics of patients with traumatic SCI as a complication to AS in order to develop prevention of SCI in patients with AS. METHODS: Patient data was gathered from the patient register covering all Finnish patients with traumatic SCI (n = 1,103) rehabilitated at Käpylä Rehabilitation Centre from the year 1979 to 1998. The patient journals were subjected to a detailed and systematic analysis. Data about patients with a history of AS (n = 19; 18 men, 1 woman) was then compared to the data about all the patients with SCI (n = 1,103; 902 men, 201 women). RESULTS: Based on the national prevalence data, the incidence rate of patients with AS for traumatic SCI was found to be 11.4 times greater than expected for the population at large. The mean age of the patients with AS was clearly higher (55.3 yrs) than the mean age of the whole group of patients (36.4 yrs) with traumatic SCI. The neurologic injury was at the cervical level in 84% of the patients with AS, but only in 48% of the patients with traumatic SCI in general. Among the patients with AS, the SCI was caused by slipping in 53% of the cases, whereas slipping was the reason for SCI only in 7% of the cases in general. CONCLUSION: Patients with AS seem to run a higher risk of traumatic SCI than the people at large, and the injury levels are higher. In particular, male patients with advanced AS should be instructed to install preventive devices such as night lights and handrails, supports or head rests when driving a car, and they should avoid walking on slippery surfaces, loose carpets etc. They also should be encouraged to avoid excessive use of alcohol and activities involving the risk of physical injury such as contact sports.

Cathepsin G in degenerating and healthy discal tissue.

OBJECTIVES: To assess the eventual presence, tissue localization, molecular forms, amount and activity of cathepsin G in the annulus fibrosus. METHODS: Normal non-autolytic disc tissue was collected from cadavers within six hours after death. Degenerate disc samples were collected from low back pain patients undergoing anterior interbody fusion due to severe, discographically verified and painful disc degeneration, and from the posterior parts of intervertebral discs from 10 patients undergoing microscopic discoidectomy because of intervertebral herniation. Avidin-biotinperxidase complex staining of cathepsin G was quantitated by morphometry. Cellular localization was analyzed using double immunofluorescence staining of cathepsin G and CD68, proline 4-hydroxylase or von Willebrand factor. Neutral salt extracts were analyzed by using synthetic cathepsin G substrate in spectrophotometry, dot-immunoblotting and Western blotting. RESULTS: Histological and morphometric image analysis showed increased cellularity, increased numbers of cathepsin G positive cells and neovascularization in degenerated discs compared to control discs. Neutral salt extract of disc tissue, degenerated or normal, in contrast to control material from synovial capsular tissue, did not contain measurable cathepsin G activity, although immunoreactive enzyme was detected in dot-immunoblotting. Western blotting demonstrated that the discal cathepsin G had an apparent molecular weight of 27 kDa. CONCLUSION: Due to its properties and localization in normal and pathologically altered tissue, cathepsin G probably plays both a direct and an indirect role in extracellular matrix degradation in the annulus fibrosus. Extracted cationic cathepsin G was immunoreactive, but was functionally inhibited by serpins or, more likely, by polyanionic proteoglycans and saccharins derived from the connective tissue matrix of the annulus fibrosus.

Factors predicting the result of surgery for lumbar intervertebral disc herniation.

The prospective study was undertaken to find out preoperative or perioperative factors predicting the results of the first surgery for lumbar disc herniation. The results were evaluated 1 and 6 months postoperatively using, in addition to the patient evaluation, indices for pain, activities of daily living (ADL), and working capacity. The best result was achieved if the patient was operated on before 2 months' duration of disabling sciatica. The operative finding graded as protrusion predicted poor result. The social and psychological factors influenced the outcome more than the findings in the preoperative physical examination or the grade of operative finding. It is recommended to add indices for pain and ADL and a psychological test to the preoperative examinations of patients with lumbar disc herniation.

Effect of intensive training on the isokinetic strength and structure of lumbar muscles in patients with chronic low back pain.

STUDY DESIGN: This study investigated the effects of the intensive physical rehabilitation program on the trunk and knee extensor muscles in patients with chronic low back pain. At baseline and after 3 months, strength was measured and muscle biopsies were taken. OBJECTIVES: To evaluate the effects of strength exercises on the structure of back muscles. SUMMARY OF BACKGROUND DATA: Rehabilitation designed for chronic low back pain patients improves trunk muscle strength, mobility of the spine, and the patients' functional capacity. The effects of such programs on the structure of back muscles have not been reported previously. METHODS: Thirty patients with chronic low back pain volunteered to participate in the study. Biopsies were taken from the multifidus and vastus lateralis muscles. The sizes of Types 1 and 2 muscle fibers were measured. The peak-torques of isokinetic trunk and knee extension were determined at two different angular velocities. RESULTS: Strength increased by 19-22% (P < 0.05) in trunk extension and by 7-11% (P < 0.05) in knee extension. Type 1 fibers maintained their pre-exercise size. The size of Type 2 muscle fibers in men increased by 11% (P < 0.05) in the multifidus and by 8% (P < 0.05) in the vastus lateralis. In women, the corresponding increases were 11% (P = 0.16) and 11% (P < 0.05). The correlation between the size of Type 2 muscle fibers in the multifidus and the strength of trunk extension improved, especially in men at follow-up. CONCLUSIONS: The results of the present study suggest that training with maximal or submaximal effort may reverse the selective atrophy of Type 2 fibers in the multifidus muscles in men. Intensive training also can significantly increase the trunk extension strength in women, but women may need a longer training period than men to achieve significant structural changes in their back muscles.

Leg-length inequality in people of working age. The association between mild inequality and low-back pain is questionable.

Leg-length inequality was measured from radiographs at the level of the vertices of the femoral heads in 247 men and women aged 35-54 years. Of these, 53 had never had any low-back problem, but they had considerable variation in leg-length inequality (mean SD, 5.5 +/- 4.1 mm; range, up to 20 mm). This group of symptom-free individuals did not differ from a group of 78 persons who had disabling low-back pain (LBP) during the previous 12 months (mean SD, 5.3 +/- 4.0 mm; range, up to 17 mm). The adjusted relative risks (odds ratios) of having LBP ever and of disabling pain during the last 12 months were 0.78 (95% confidence interval, 0.43-1.17) and 1.02 (0.68-1.38), respectively, for an increase of 5 mm in leg-length inequality. The results from this study make an association between mild leg-length inequality and LBP questionable.

Isokinetic and non-dynamometric tests in low back pain patients related to pain and disability index.

STUDY DESIGN: This study compared isokinetic and non-dynamometric tests for their correlation with subjective low back pain symptoms. METHODS: A total of 185 patients with chronic low back pain were examined. RESULTS: The repetitive arch-up and sit-up tests correlated significantly with pain and disability (Million index) both in men and women (r ranged from -0.39 to -0.46; P < 0.001). In women, the isokinetic trunk flexion and extension tests and the non-dynamometric tests correlated equally well with the Million index. In men, the isokinetic flexion and extension tests had weaker correlations. Overall, the isokinetic lifting tests showed lower correlations than did the isokinetic trunk extension tests. In the isokinetic flexion and extension tests, fast testing speeds (120 degrees/sec and 150 degrees/sec) correlated somewhat better with the subjective symptoms than did the lowest speed (30 degrees/sec). CONCLUSIONS: The non-dynamometric tests are still useful in clinical practice in spite of the development of more accurate muscle strength evaluation methods.

Mechanisms explaining the association between low back trouble and deficits in information processing. A controlled study with follow-up.

STUDY DESIGN: A controlled study with a 6-month follow-up period. OBJECTIVES: To find an explanation for the association between impairment in information processing, i.e., slow reaction times, and chronic low back trouble. SUMMARY OF BACKGROUND DATA: Low back trouble, chronic pain in general, and depression have been associated with impaired cognitive functions and slow reaction times. It is a common phenomenon that the preferred hand performs better than the nonpreferred hand in motor tasks. The authors hypothesized that chronic low back trouble hampers the functioning of short-term memory in a way that leads the preferred hand to loose its advantage over the nonpreferred hand, but that the advantage would be restored during the rehabilitation. METHODS: Sixty-one healthy control subjects and 68 patients with low back trouble participated in the study. Reaction times for the preferred and nonpreferred upper limbs were tested. A multiway analysis of covariance was used to examine the group, handedness, and rehabilitation effects on reaction times. The hypothesis was specifically tested with a third-degree interaction: group-handedness-rehabilitation. RESULTS: A significant interaction among group, handedness, and rehabilitation was found (P = 0.05). At the beginning, the reaction times for the preferred hand were faster among the control subjects (P = 0.001), but not among the patients with low back trouble (P = 0.62). After the rehabilitation, the preferred hand was faster both among the control subjects (P = 0.001) and the patients with low back trouble (P = 0.0002). During the rehabilitation, back pain, psychological distress, and general disability decreased significantly among the patients with chronic low back trouble. CONCLUSIONS: The results support the hypothesis that chronic low back trouble (i.e., pain, psychological distress, and general disability) hampers the functioning of short-term memory, which results in decreased speed of information processing among patients with chronic low back trouble.

Anthropometric measurements and the incidence of low back pain in a cohort of pubertal children.

STUDY DESIGN: The authors studied the anthropometric measurements to predict low back pain (LBP) in a cohort of growing adolescents. SUMMARY OF BACKGROUND DATA: The cohort consisted of all the fourth-grade school children of the western school district of Helsinki, Finland, in the spring of 1986. They were examined annually from the mean age of 11.8 to 13.8 years. METHODS: The forward bending test, measurements of total arm length, pelvic equilibrium, and spinal pantographs were carried out by the same physiatrist. A standardized pain questionnaire presented at the final examination obtained the history of LBP. Of the original cohort of 1060 children, those 859 (408 girls and 451 boys) who participated in all the examinations and had not had LBP until the age of 12.8 years were included in this study. RESULTS: The 1-year (from 12.8 to 13.8 years) incidence of LBP was 18.4% in girls and 16.9% in boys. Trunk asymmetry measured by the forward bending test and sitting height were significant determinants of the incidence of LBP. In the whole cohort, the odds ratio (OR) of trunk asymmetry adjusted for all the other risk determinants was 1.19 and its confidence interval (CI) was 1.00-1.39 per one standard deviation increase of the trunk hump. In the multivariate analysis comprising both sexes, OR per one standard deviation increase of sitting height was 1.24, (95% CI 1.03-1.46). In boys, standing height (OR 1.40, 95% CI 1.13-1.65, per one standard deviation) and sitting height (OR 1.35, 95% CI 1.09-1.63, per one standard deviation) were positively associated with the risk of LBP. These associations were not significant in girls. CONCLUSIONS: Sitting height and trunk asymmetry may contribute to LBP in pubertal children. The role of anthropometric characteristics seems, however, modest.

The lumbar multifidus muscle five years after surgery for a lumbar intervertebral disc herniation.

Biopsy specimens of the lumbar multifidus were obtained from 18 patients with lumbar disc herniation at operation and after a postoperative follow-up period of 5 years. The structure and morphometry of the muscle fibers were analyzed and these data were compared with intraoperative biopsy results and the clinical outcome of the operation. The main findings were: 1) on the basis of occupational handicap score 10 patients belonged in the "positive" and 8 in the "negative" outcome group; 2) the intraoperatively recorded selective type 2 muscle fiber atrophy and the extent of pathologic inner structure changes both decreased in the "positive" outcome group, whereas they persisted in the "negative" group; 3) grouping as a definite sign of reinnervation was seen in only two versus four patients of the "positive" versus "negative" outcome group; 4) the relative amount of adipose tissue within the muscle decreased more markedly in the "positive" outcome group. The authors propose that both inactivity and axonal injury (mainly of neurapraxia type) contribute to the selective type 2 atrophy and inner structure changes in disc patients' multifidus muscle. These pathologic structural changes correlated well with the clinical outcome, and most importantly they are reversible and can be diminished by adequate therapy.

Psychomotor speed and postural control in chronic low back pain patients A controlled follow-up study.

STUDY DESIGN: Psychomotor speed (reaction time) and postural control (center point of force velocity) among healthy control volunteers and patients with chronic low back pain (LBP) were studied at the beginning of an active, functional, restoration back rehabilitation program and 5 months after the program. OBJECTIVES: To study cross-sectionally reaction times and center points of force velocity among control volunteers and patients with low back pain, and to evaluate the effects of the restoration on these measures of motor function in a follow-up examination. SUMMARY OF BACKGROUND DATA: Deficits of motor skills and of coordination have been reported in association with musculoskeletal disorders, but one can only speculate about an association between proprioceptive dysfunction and low back disorders on the basis of the currently available data. METHODS: Sixty-one healthy control volunteers and 99 patients with low back pain-68 of these patients experienced moderate pain; 31 experienced severe pain-participated in the study. Reaction times for upper and lower limbs were tested with a system based on a microcomputer. Postural stability was measured with a vertical force platform. RESULTS: A consistent trend was found in which patients with low back pain had reaction times slower than these of control volunteers. Man with severe low back pain had significantly longer hand reaction times than men in the control group (P = 0.03). Women with severe low back pain also had poorer postural control than women with moderate low back pain (P = 0.02) and women in the control group (P = 0.04). Functional restoration seemed to have an effect on reaction times. The restoration was considered successful if the condition of a patient with a disability that had resulted from low back pain improved during the follow-up examination and unsuccessful if the disability worsened. Patients who experienced these results were identified in groups called "good" and "poor," respectively. Among men, the reaction times improved in the control group and "good" groups, but they became slower in the "poor" group. The difference between "good" and "poor" groups was significant (P = 0.008). Women in the "good" group achieved the most improved reaction times, and the difference between these women and the control women almost reached significance (P = 0.076). CONCLUSION: The results indicate that patients with chronic low back pain have impaired psychomotor speed and, among women, impaired postural control. Psychomotor speed improved during an active, functional, restoration back rehabilitation program.

Arm motion speed and risk of neck pain. A preliminary communication.

STUDY DESIGN: A sample of 486 Helsinki City Council workers, 35 to 54 years of age, was examined twice at a 1-year interval. OBJECTIVES: To investigate the speed of repetitive arm motion for its ability to predict neck pain. SUMMARY OF BACKGROUND DATA: Psychomotor factors have been suggested to play a role in the etiology of spinal disorders. It was hypothesized that motor skills, as reflected by arm motion speed, could provide protection against neck pain. METHODS: Both the baseline and follow-up examinations consisted of a questionnaire on the history of neck pain and of a number of tests, including arm motion speed and static and dynamic strength of the upper extremities. RESULTS: Of the 124 men and women who reported not having had neck pain during the 1 year before the baseline examination, 23 (19%) reported neck pain on reexamination. The incidence of neck pain was significantly higher both in the least and most rapid quintiles of arm motion speed than in the medium quintiles. This association was not confounded by age, sex, smoking, physical activity at work or at leisure, psychological distress score, or strength measures of the upper extremities, although these factors were significant covariates of the arm motion speed at baseline. When adjusted for these factors, the odds ratios of neck pain in the most and least rapid quintiles of arm motion speed were 8.68 (95% confidence interval 1.85-40.75) and 9.57 (95% confidence interval 2.21-41.52) respectively, compared with the medium quintiles. CONCLUSIONS: These results suggest that people with either very slow or very rapid arm motion speed may have an increased risk of neck pain. The etiology of neck pain is probably different on these two occasions.

One-footed and externally disturbed two-footed postural control in patients with chronic low back pain and healthy control subjects. A controlled study with follow-up.

STUDY DESIGN: A study of postural control during one-footed and externally disturbed two-footed stance among healthy control subjects and patients with chronic low back pain at the beginning of a functional back restoration program and 6 months later at follow-up examination. OBJECTIVES: To study postural control cross-sectionally among control subjects and patients with low back pain, and to evaluate the effects of functional restoration on the postural control parameters in a follow-up examination. SUMMARY OF BACKGROUND DATA: Deficits of motor skills and coordination have been reported in association with musculoskeletal disorders. It has been found that patients with chronic low back pain have impaired psychomotor control, but the impairment is reversible with successful low back rehabilitation. It is insufficiently known how functional activation and intensive physical training affect postural control. METHODS: Sixty-one healthy volunteers (32 men, 29 women) and altogether 99 patients with low back pain participated in the study. Sixty-eight patients (33 men, 35 women) had moderate and 31 (18 men, 13 women) had severe low back pain. Postural stability was measured with a force platform. In two-footed stance, vibration stimulation on calf and back muscles was used to disturb the balance. Center point of force-velocity (cm/sec), average position shift in anteroposterior direction (cm), and maximal position shift in lateral direction (cm) were used as the parameters. RESULTS: Reliability of all tests was acceptable. Center point of force-velocity was the most sensitive parameter and the one-footed measurement the most sensitivetest for evaluating postural stability. At the beginning, the patients with severe low back pain had poorer one-footed postural control compared with the control subjects (P = 0.0003). The subgroup of patients with moderate low back pain participated in the restoration program. The outcome of the restoration program was considered good if the disability because of low back pain (Oswestry index) decreased during the restoration program and poor if the disability increased or did not change. The one-footed postural stability remained primarily at the same level as the initial results in the control and good outcome groups, but became significantly poorer in the poor outcome group. The difference between poor outcome and control groups was statistically significant (P = 0.04). CONCLUSIONS: Impaired postural stability seems to be one factor in multidimensional symptomatology of patients with chronic low back trouble. Postural stability is easily disturbed in case of impairment in strength, coordination, or effective coupling of muscles in the lumbar and pelvic area. Patients with chronic low back pain seem to experience impairment in these functions, which should be taken into consideration when back rehabilitation programs are planned.

Intensive physical and psychosocial training program for patients with chronic low back pain. A controlled clinical trial.

STUDY DESIGN: The authors conducted a controlled clinical trial with 1-year follow-up to define the effectiveness of an intensive physical and psychosocial training program on patients with low back pain. SUMMARY OF BACKGROUND DATA: The intervention group included 152 patients (mean age 40.5 yr, Million index 45.1/100), and the reference group included 141 patients (mean age 40.4 yr, Million-index 44.5/100). METHODS: The progressive intervention program consisted of intensive physical training and psychosocial activation. The outcomes were physical and psychosocial measures, the pain and disability index (Million), sick leaves, and occupational handicap. RESULTS: The intervention was more efficient with respect to physical measures and pain and disability index. There were only mild or no differences in changes between the study groups in psychologic variables, sick leaves, or retirement. CONCLUSIONS: The intervention program could improve physical disability, but to improve occupational handicap, activities of the whole society (social legislation, labor market policy) are needed.

The multifidus muscle in patients with lumbar disc herniation. A histochemical and morphometric analysis of intraoperative biopsies.

Structural changes in the multifidus muscle were analyzed in 41 patients operated on for herniated intervertebral disc. Twelve cadavers served as controls. The two main findings follow: Both in the patients and in the controls the Type 2 muscle fibers were markedly and selectively smaller than the Type 1 fibers, which were of normal size for striated muscles, and the internal structure of Type 1 fibers showed so-called core-targetoid and/or moth-eaten change. Group atrophy or fiber-type grouping (indicators of denervation and reinnervation) were observed only in a few patients. The selective small size of the Type 2 fibers may indicate atrophy due to relative inactivity of the multifidus muscle both in the patients and in the controls, ie, it does not need to be related to the herniated disc. Definite proof for denervation of the multifidus muscle was not observed, but neither the possibility be excluded. The cause of the core-targetoid and/or moth-eaten changes cannot yet be determined with certainty, because these changes are not specific for any single entity but may be due, for example, to denervation, ischemia, or altered use of the muscles because of pain. In any case, because the changes were significantly more common in the patients than in the controls, they signal for a pathologic condition, the character of which remains to be elucidated.

A prospective study of patients with sciatica. A comparison between conservatively treated patients and patients who have undergone operation, Part I: Patient characteristics and differences between groups.

Based on a prospective study on 342 sciatica patients examined with rhizography, the aim was to determine which factors others than the rhizography finding and the grade and duration of symptoms were related to the selection of patients to undergo operation. Compared with surgically treated patients, conservatively treated patients who did not undergo operation and who had pathologic rhizography findings had pessimistic attitudes to possible surgery, often expressed a desire to retire, and considered their work as physically stressful. The women in this group were older and had lower pain indices than women who underwent operation. Conservatively treated patients with negative rhizography had more severe occupational handicaps, minor expectations of possible surgery, physically more strenuous jobs requiring difficult physical positions, and lower indices for pain and ADL than did the operated patients. The social and ergonomic background problems are emphasized in sciatica patients conservatively treated after rhizography.

A prospective study of patients with sciatica. A comparison between conservatively treated patients and patients who have undergone operation, Part II: Results after one year follow-up.

The prospective study included 122 sciatica patients who had not undergone operation (NOPs) and 220 sciatica patients who had undergone operation (OPs); all had been examined by rhizography. The follow-up study was done on 110 (90%) of the NOPs and 212 (96%) of the OPs. The NOPs were divided into two groups: 30 patients with pathologic rhizography (PR) and 80 patients with negative rhizography (NR). Pain-, ADL-, and occupation-handicap indices showed that after the 1 year follow-up the OP group had the best result and the NR group the lowest result. The PR group had nearly as good a result as the OP group. Thus, sciatica patients are candidates for conservative therapy, even though they have pathologic findings in rhizography, if the symptoms are mild. To improve therapeutic outcome, more accurate diagnostic tools are needed to develop specific therapy especially for those sciatica patients with negative rhizography.

Connective tissue changes of the multifidus muscle in patients with lumbar disc herniation. An immunohistologic study of collagen types I and III and fibronectin.

The connective tissue components, Types I and III collagen fibronectin, were immunohistologically analyzed using their specific antibodies for localization and semiquantitative estimation in 24 patients (11 women and 13 men, all under 55 years of age) operated on for herniated lumbar intervertebral disc. Nine cadavers without known back problems (2 women, 7 men) served as controls. In controls, Type I collagen was present in the endo- and perimysial structures of the muscle, more conspiciously in the former. Type III collagen, together with fibronectin, were more abundant in the perimysium than in the endomysium. Thickening of these structures was not evident in the controls. In most patients Types I and III collagen and fibronectin distribution was similar to that of the controls. However, fibrotic changes of both and endo- and perimysial structures involved all Types I and III collagen and fibronectin in ten cases. In two patients an increase in Type I collagen staining intensity in the endomysium was recorded and thickening of the endomysial structures was observed in six patients. There were correlations with the severity of the connective tissue structural changes to atrophy of the muscle and furthermore to disability of the patient in the 1-year postoperative check-up. These findings suggest that if marked fibrosis of the muscle occurs, it can be a factor impairing recovery from the disease during the long-term postoperative course.

Neuropathy and the automatic analysis of electromyographic signals from vibration exposed workers.

An automatic analysis of the electromyographic activity of the extensor digitorum communis, first dorsal interosseus and opponens pollicis muscles was performed, and both motor and sensory conduction velocities of the median and ulnar nerves were measured in the study of neuropathic changes that occur in traumatic vasospastic disease. Twenty-eight forest workers and 10 pneumatic-tool operators, all with a long occupational exposure to local vibration of the hands, were studied with these neurophysiological methods and general clinical and roentgenological examinations. Twenty male manual workers with a similar age distribution served as the comparison group. The most sensitive measures which separated the subjects with traumatic vasospastic disease from the nonexposed workers were the conduction velocity of the slower motor fibers of the ulnar nerve, the distal sensory conduction velocity and the motor distal latency of the median nerve. The duration and rise time of the averaged muscular potentials of intrinsic hand muscles correlated especially with those nerve conduction velocities which were the most sensitive in exhibiting neuropathic changes.

Performance capacity of trunk muscles in ankylosing spondylitis.

The comparative results of four tests (a dynamometer, a single and a repetitive dynamic and a static test) to determine the performance capacity of trunk muscles in ankylosing spondylitis are reported. Seventeen men and four women, aged 31 to 35 yrs, were examined. Trunk muscle performance was compared with the flexion mobility of the spine and ESR. The best correlation between muscle capacity of trunk extensors and spinal mobility was seen in the static trunk extensor test. The best correlation between muscle capacity of trunk flexors and spinal mobility was seen in the single dynamic test. Because the comprehensive exercise therapy including muscle strengthening is supported by our results and there is no generally recommended test for evaluating the performance capacity of trunk muscles, it seems reasonable to develop such tests of trunk muscles for clinical assessment of ankylosing spondylitis. Clinical trials to ensure the positive effect of well trained trunk muscles in ankylosing spondylitis are still lacking.