Protein homeostasis in LGMDR9 (LGMD2I) - The role of ubiquitin-proteasome and autophagy-lysosomal system

AIMS

Limb-girdle muscular dystrophy R9 (LGMDR9) is an autosomal recessive disorder caused by mutations in the fukutin-related protein gene (FKRP), encoding a glycosyltransferase involved in α-dystroglycan modification. Muscle atrophy, a significant feature of LGMDR9, occurs by a change in the normal balance between protein synthesis and protein degradation. The ubiquitin-proteasome system (UPS) and autophagy-lysosomal system play a key role in protein degradation in skeletal muscle cells, but their involvement in the pathology of LGMDR9 is still largely unknown. We have aimed at clarifying whether proteolysis through the UPS and the autophagy-lysosomal pathway is dysregulated in LGMDR9 patients.

METHODS

Vastus lateralis biopsies from 8 normal controls and 12 LGMDR9 patients harbouring the c.826C>A/c.826C>A FKRP genotype were assessed for protein markers related to UPS, the autophagy-lysosomal system and endoplasmic reticulum (ER) stress/unfolded protein response (UPR), followed by ultrastructural analysis by transmission electron microscopy (TEM).

RESULTS

Protein levels of E3 ubiquitin ligases Atrogin-1 and MuRF1 showed a pattern similar to normal controls. Elevation of the autophagy markers Atg7, LC3B-II, decreased level of p62 as well as downregulation of the negative autophagy regulator mTORC1, indicated an activation of autophagy in LGMDR9. Mitophagy markers Bnip3 and Parkin were decreased. TEM analysis demonstrated accumulation of autophagosome-like structures in LGMDR9 muscle. There was also an increase in the expression of ER stress/UPR markers PDI, peIF2α and CHOP and a decrease in IRE1α. However, GRP94, Bip and Calnexin remained unchanged.

CONCLUSION

Our findings indicate that autophagy and ER stress are induced in LGMDR9 muscle.

Maximal strength training in patients with Parkinson's disease: impact on efferent neural drive, force-generating capacity, and functional performance

Parkinson's disease (PD) is characterized by progressive neurological deterioration, typically accompanied by reductions in skeletal muscle force-generating capacity (FGC) and functional performance. Physical activity has the potential to counteract this debilitating outcome, however, it is elusive if high-intensity strength training included in conventional treatment may improve results. Therefore, we randomly assigned 22 PD patients (74 ± 9 yr) to conventional rehabilitation with or without maximal strength training (MST) performed as leg press and chest press at ~90% of one repetition maximum (1RM), five times per week for 4 wk. FGC, physical performance, and efferent neural drive assessed as evoked potentials (V-wave normalized to M-wave in m. soleus) were measured following training. Results revealed that only MST improved 1RM leg press (101 ± 23 to 118 ± 18 kg) and chest press (36 ± 15 to 41 ± 15 kg), plantar flexion maximal voluntary contraction (235 ± 125 to 293 ± 158 N·m), and rate of force development (373 ± 345 to 495 ± 446 N·m·s^-1; all P < 0.05; different from controls P < 0.05). FGC improvements were accompanied by an increased efferent neural drive to maximally contracting musculature (V-to-M ratio: 0.17 ± 0.12 to 0.24 ± 0.15; P < 0.05; different from controls P < 0.05), improved physical performance (stair climbing: 21.0 ± 9.2 to 14.4 ± 5.2 s; timed up and go: 7.8 ± 3.3 to 6.2 ± 2.5 s; both P < 0.05), and self-perceived improvement in health (3.1 ± 0.5 to 2.6 ± 0.9) and social activities functioning (2.2 ± 1.0 to 1.5 ± 1.1; both P < 0.05). No changes were observed in the control group. In conclusion, this study shows that MST improves FGC, neuromuscular function, and functional performance and advocates that high-intensity strength training should be implemented as an adjunct therapy in the treatment of PD patients.NEW & NOTEWORTHY This randomized, controlled trial documents that supervised high-intensity strength training improves efferent neural drive, maximal muscle strength, rate of force development, and functional performance in patients with Parkinson's disease (PD). In contrast, no differences were observed in these outcome variables in patients receiving conventional treatment consisting of recreational physical activity with low-to-medium intensity. Consequently, this study advocates that high-intensity strength training should be implemented in the clinical treatment of PD patients.

Mechanical oscillations superimposed on the pelvic floor muscles during Kegel exercises reduce urine leakage in women suffering from stress urinary incontinence: A prospective cohort study with a 2-year follow up

INTRODUCTION

New methods of conservative treatment of female stress urinary incontinence are needed. We investigated whether superimposed vibration mechanosignals during Kegel exercises could reduce the amount of urinary leakage after 4 and 6 weeks of training.

MATERIAL AND METHODS

Sixty women with stress urinary incontinence were included in this prospective cohort study. Vibration mechanosignals were superimposed during Kegel exercises using an intravaginal device. Each training session consisted of 15 maximal contractions of pelvic floor muscles for 5 s. The women performed training (5 min/day) at home for 4 (n = 60) and 6 (n = 36) weeks. Urine leakage (g) during stress test with standardized bladder volume, and contraction force without and with superimposed mechanical stimulations were measured at inclusion (T₀ ), and after 4 (T₂ ) and 6 (T₃ ) weeks of training using an intravaginal device. Incontinence Questionnaire-Short Form was recorded at T₀ , and in a sub-cohort of women (n = 36) at 2 years follow up.

RESULTS

Mean urine leakage reduced significantly from 20.5 (± 12.2) g at T₀ to 4.8 (± 6.7) g at T₂ and 1.5 (± 6.7) g at T₃ . After 4 and 6 weeks of training, urinary leakage was ≤ 4 g on stress test in 44 and 49 of the 60 women, respectively. At T₀ , the mean Incontinence Questionnaire-Short Form score was 13 (± 2.4), and at 2 years follow up, the score was 6.3 (± 3.75).

CONCLUSIONS

Superimposed mechanical stimulation with Kegel exercises significantly reduced urinary leakage in women with stress urinary incontinence.

Arm Cycling Combined with Passive Leg Cycling Enhances VO2peak in Persons with Spinal Cord Injury Above the Sixth Thoracic Vertebra

Objective: To test whether passive leg cycling (PLC) during arm cycling ergometry (ACE) affects peak oxygen uptake (VO2peak) differently in individuals with spinal cord injury (SCI) at/above the 6th thoracic vertebra (T6) and below T6. Methods: We conducted a cross-sectional study, analyzed by univariate and multivariate regression models. Between- and within-group differences were examined during (a) ACE only, (b) ACE combined with PLC (ACE-PLC), and (c) ACE combined with functional electrical stimulation cycling (FES hybrid). Fifteen SCI subjects were recruited and grouped according to injury level: at/above T6 (SCI-high, n = 8) or below T6 (SCI-low, n = 7). VO2peak tests during ACE only, ACE-PLC, and FES hybrid were performed in random order on separate days. Results: In the SCI-high group, mean (SD) VO2peak was 19% higher during ACE-PLC than during ACE only [21.0 (3.8) vs 17.7 (5.0) mL·kg-1·min-1; p = .002], while VO2peak during FES hybrid cycling was 16% higher than during ACE-PLC [24.4 (4.1) mL·kg-1·min-1; p = .001]. No significant differences among exercise modalities were found for the SCI-low group. Conclusion: Additional training modalities (eg, PLC) during ACE facilitate exercise in SCI-high individuals, but not to the level of the FES hybrid method. Conversely, additional training modalities may not increase training load in SCI-low individuals.

Impact of maximal strength training on work efficiency and muscle fiber type in the elderly: Implications for physical function and fall prevention

Although aging is typically associated with a decreased efficiency of locomotion, somewhat surprisingly, there is also a reduction in the proportion of less efficient fast-twitch Type II skeletal muscle fibers and subsequently a greater propensity for falls. Maximal strength training (MST), with an emphasis on velocity in the concentric phase, improves maximal strength, the rate of force development (RFD), and work efficiency, but the impact on muscle morphology in the elderly is unknown. Therefore we evaluated force production, walking work efficiency, and muscle morphology in 11 old (72±3years) subjects before and after MST of the legs. Additionally, for reference, the MST-induced morphometric changes were compared with 7 old (74±6years) subjects who performed conventional strength training (CST), with focus on hypertrophy, as well as 13 young (24±2years) controls. As expected, MST in the old improved maximal strength (68%), RFD (48%), and work efficiency (12%), restoring each to a level similar to the young. However, of importance, these MST-induced functional changes were accompanied by a significant increase in the size (66%) and shift toward a larger percentage (56%) of Type II skeletal muscle fibers, mirroring the adaptations in the hypertrophy trained old subjects, with muscle composition now being similar to the young. In conclusion, MST can increase both work efficiency and Type II skeletal muscle fiber size and percentage in the elderly, supporting the potential role of MST as a countermeasure to maintain both physical function and fall prevention in this population.

Physical examination tests of the shoulder: a systematic review and meta-analysis of diagnostic test performance

BACKGROUND

Physical examination tests of the shoulder (PETS) are clinical examination maneuvers designed to aid the assessment of shoulder complaints. Despite more than 180 PETS described in the literature, evidence of their validity and usefulness in diagnosing the shoulder is questioned.

METHODS

This meta-analysis aims to use diagnostic odds ratio (DOR) to evaluate how much PETS shift overall probability and to rank the test performance of single PETS in order to aid the clinician's choice of which tests to use. This study adheres to the principles outlined in the Cochrane guidelines and the PRISMA statement. A fixed effect model was used to assess the overall diagnostic validity of PETS by pooling DOR for different PETS with similar biomechanical rationale when possible. Single PETS were assessed and ranked by DOR. Clinical performance was assessed by sensitivity, specificity, accuracy and likelihood ratio.

RESULTS

Six thousand nine-hundred abstracts and 202 full-text articles were assessed for eligibility; 20 articles were eligible and data from 11 articles could be included in the meta-analysis. All PETS for SLAP (superior labral anterior posterior) lesions pooled gave a DOR of 1.38 [1.13, 1.69]. The Supraspinatus test for any full thickness rotator cuff tear obtained the highest DOR of 9.24 (sensitivity was 0.74, specificity 0.77). Compression-Rotation test obtained the highest DOR (6.36) among single PETS for SLAP lesions (sensitivity 0.43, specificity 0.89) and Hawkins test obtained the highest DOR (2.86) for impingement syndrome (sensitivity 0.58, specificity 0.67). No single PETS showed superior clinical test performance.

CONCLUSIONS

The clinical performance of single PETS is limited. However, when the different PETS for SLAP lesions were pooled, we found a statistical significant change in post-test probability indicating an overall statistical validity. We suggest that clinicians choose their PETS among those with the highest pooled DOR and to assess validity to their own specific clinical settings, review the inclusion criteria of the included primary studies. We further propose that future studies on the validity of PETS use randomized research designs rather than the accuracy design relying less on well-established gold standard reference tests and efficient treatment options.

Demand, Control and Support at Work Among Sick-Listed Patients with Neck or Back Pain: A Prospective Study

Purpose The main aim of this study was to assess changes in perceived demand, control and support at work of neck and back pain patients over 1 year. We also hypothesised that perceived changes in demand, control and support at work were associated with clinical improvement, reduced fear-avoidance beliefs and successful return to work. Methods Four hundred and five sick-listed patients referred to secondary care with neck or back pain were originally included in an interventional study. Of these, two hundred and twenty-six patients reported perceived psychosocial work factors at both baseline and 1-year follow-up, and they were later included in this prospective study. Changes in demand, control and support dimensions were measured by a total of nine variables. Results At the group level, no significant differences were found among the measured subscales. At the individual level, the regression analyses showed that decreases in fear-avoidance beliefs about work were consistently related to decreases in demand and increases in control, whereas decreases in disability, anxiety and depression were related to increases in support subscales. Conclusions The perception of demand, control and support appear to be stable over 1 year in patients with neck and back pain, despite marked improvement in pain and disability. Disability, anxiety, depression and fear-avoidance beliefs about work were significantly associated with the perception of the work environment, whereas neck and back pain were not.

The effect from maximal bench press strength training on work economy during wheelchair propulsion in men with spinal cord injury

OBJECTIVE

To assess the effect from maximal bench press strength training (MST) on wheelchair propulsion work economy (WE).

STUDY DESIGN

Pretest-posttest case-control group design.

SETTING

St Olavs Hospital, Trondheim, Norway.

METHODS

Seventeen male individuals with spinal cord injury (SCI) paraplegia were allocated to either MST bench press (n=11) or the control group (CG) (n=7). The MST group trained bench press three times per week, for 6 weeks, starting at 85-95% of their pretest bench press one-repetition maximum (1RM). For calculation of WE during wheelchair propulsion, oxygen uptake (VO₂) measurements were collected during wheelchair ergometry (WCE) at submaximal workload of 50 W. Similarly, peak oxygen uptake (VO_2peak) and peak power output (W) were measured during WCE.

RESULTS

Individuals in the MST regimen significantly improved WE compared with the CG by 17.3 % (mean between-group differences: 95% confidence interval) of 2.63 ml kg^-1 min^-1: (-4.34, -0.91) (P=0.007). Between pretest and posttest, the increase in bench press 1RM was by 17% higher in the MST group compared with the CG. At peak testing, the MST group generated significantly higher peak power compared with the CG. All other physiological variables were comparable within and between groups.

CONCLUSIONS

A 6-week MST bench press regimen significantly improved WE during wheelchair propulsion at 50 W workload. These preliminary data support a possible beneficial role for MST to reduce the energy cost of wheelchair propulsion for SCI individuals.

Measurement Properties of the Nordic Questionnaire for Psychological and Social Factors at Work: A Rasch Analysis

The main aim of this study was to evaluate the measurement properties of the Nordic Questionnaire for Psychological and Social Factors at Work (QPS Nordic) and the domains of demand, control and support. The Rasch analysis (RUMM 2030) was based on responses from 226 subjects with back pain who completed the QPS Nordic dimensions of demand, control, and social support (30 items) at one year follow up. The Rasch analysis revealed disordered thresholds in a total of 25 of the 30 items. The domains of demand, control and support fit the Rasch model when analyzed separately. The demand domain was well targeted, whereas patients with current neck and back pain had lower control and higher support than reflected by the questions. Two items revealed DIF by gender, otherwise invariance to age, gender, occupation and sick-leave was documented. The demand, control support domains of QPS Nordic comprised unidimensional constructs with adequate measurement properties.

Age and pro-inflammatory gene polymorphisms influence adjacent segment disc degeneration more than fusion does in patients treated for chronic low back pain

PURPOSE

Does lumbar fusion lead to accelerated adjacent segment disc degeneration (ASDD) or is it explained by genetics and aging? The influence of genetics on ASDD remains to be explored. This study assesses whether the disc space height adjacent to a fused segment is associated with candidate gene single nucleotide polymorphisms (SNPs).

METHODS

Patients with low back pain from four RCTs (N = 208 fusion; 77 non-operative treatment) underwent standing plain radiography and genetic analyses at 13 ± 4 years follow-up. Disc space height was measured using a validated computer-assisted distortion-compensated roentgen analysis technique and reported in standard deviations from normal values. Genetic association analyses included 34 SNPs in 25 structural, inflammatory, matrix degrading, apoptotic, vitamin D receptor and OA-related genes relevant to disc degeneration. These were analysed for their association with disc space height (after adjusting for age, gender, smoking, duration of follow-up and treatment group) first, separately, and then together in a stepwise multivariable model.

RESULTS

Two SNPs from the IL18RAP gene (rs1420106 and rs917997) were each associated with a lower disc space height at the adjacent level (B = -0.34, p = 0.04 and B = -0.35, p = 0.04, respectively) and the MMP-9 gene SNP rs20544 was associated with a greater disc space height (B = 0.35, p = 0.04). Age (p < 0.001) and fusion (p < 0.008) were also significant variables in each analysis. The total explained variance in disc space height was for each SNP model 13-14 %, with 11-12 % of this being accounted for by the given SNP, 64-67 % by age and 19-22 % by fusion. In the multivariable regression analysis (with nine SNPs selected for entry, along with the covariates) the total explained variance in disc space height was 23 %, with the nine SNPs, age and fusion accounting for 45, 45 and 7 % of this, respectively.

CONCLUSIONS

Age was the most significant determinant of adjacent segment disc space height followed by genetic factors, specifically inflammatory genes. Fusion explained a statistically significant but small proportion of the total variance. Much of the variance remained to be explained.

Change in pain, disability and influence of fear-avoidance in a work-focused intervention on neck and back pain: a randomized controlled trial

BACKGROUND

Neck and back pain are among the most common causes of prolonged disability, and development of interventions with effect on pain, disability and return to work is important. Reduction of fear avoidance might be one mechanism behind improvement after interventions. The aim of the present study was to evaluate changes in pain and disability at the 12-month follow-up of patients with neck and back pain treated with a work-focused intervention compared to patients treated with standard interventions, and the influence of improvement fear avoidance beliefs during the interventions on pain, disability and return to work at 12-month follow-up.

METHODS

413 employed patients with back or neck pain referred to secondary care, and sick-listed between 4 weeks and 12 months, were randomized to a work-focused rehabilitation or control interventions. Follow-up was conducted 4 and 12 months after inclusion. The groups were compared (independent sample t-test) regarding differences in disability scores (Oswestry disability index/neck disability index) and pain (numeric rating scale) from baseline to 12-month follow-up. Changes in fear avoidance beliefs (FABQ) from baseline to 4 month follow-up were calculated, and the association between this change and return to work, pain and disability at 12 months were tested in stepwise multiple logistic regression models.

RESULTS

Pain and, disability scores decreased to in both the work-focused and control intervention to 12-month follow-up, and there were no significant differences between the groups. FABQ decreased similarly in both groups to 4 month follow-up. The logistic regression model revealed an association between a reduced FABQ work score at 4 months and return to work within one year (adjusted OR 3.60, 95% CI 1.19 to 10.88). Reduced FABQ physical activity score at 4 months was associated with decreased disability after 12 months (adjusted OR (3.65. 95% CI 1.43 to 9.28).

CONCLUSIONS

Short work-focused rehabilitation had the same effect on pain and disability as control interventions. Reduction in FABQ-W score after treatment seems to be an important predictor for return to work in both groups.

TRIAL REGISTRATION

Clinicaltrials.gov NCT00840697.

Fear-avoidance beliefs associated with perceived psychological and social factors at work among patients with neck and back pain: a cross-sectional multicentre study

Background

Neck and back pain are common and often account for absenteeism at work. Factors at work as well as fear–avoidance beliefs may influence sick-leave in these patients. The aims of this study were to assess: (1) how sick-listed patients in specialised care perceive demand, control, support, effort, reward, and overcommitment at work compared to a general reference group of workers; (2) if women and men report demand, control, support, effort, reward, and overcommitment differently; and (3) the association between psychological and social factors at work and fear–avoidance beliefs about work.

Methods

A cross-sectional multicentre study was carried out in 373 patients on sick leave due to neck and back pain. Psychosocial work factors were measured by demand, control, and support, (Nordic Questionnaire for Psychological and Social Factors at Work), and effort, reward and overcommitment (Effort Reward Imbalance Questionnaire). Fear avoidance beliefs about work were measured by the Fear–Avoidance Belief Questionnaire Work subscale (FABQ-W).

Results

Although the patients differed significantly from a reference working group regarding several subscales of demand, control, support, effort, reward, and overcommitment, the magnitude of these differences were small. The study population also reported significantly higher scores for ‘demand for physical endurance’ than the reference population, and Cohen’s d = 0.55 here indicated a medium degree of difference. Female patients reported significantly higher on support, whereas male patients reported significantly higher demand for physical endurance, quantitative demand, effort, and overcommitment. Demand for physical endurance, job control, job support, high reward, and overcommitment were significantly associated with FABQ-W.

Conclusions

Perceived psychological and social factors at work were strongly associated with fear–avoidance beliefs about work in sick-listed neck and back patients. The demand for physical endurance, control, support, high reward, as well as overcommittment at work outweighed pain and added to the burden of emotional distress and disability regarding fear–avoidance beliefs.

Effect of lower extremity functional electrical stimulation pulsed isometric contractions on arm cycling peak oxygen uptake in spinal cord injured individuals

OBJECTIVE

To compare peak oxygen uptake (VO2peak) between: (i) functional electrical stimulation lower extremity pulsed isometric muscle contractions combined with arm cycling (FES iso hybrid), (ii) functional electrical stimulation cycling combined with arm cycling (FES hybrid cycling), and (iii) arm cycling exercise (ACE) in individuals with spinal cord injury with level of injury above and below T6.

DESIGN

Cross-over repeated measures design. METHODS/PARTICIPANTS: Individuals with spinal cord injury (n = 15) with level of injury between C4 and T12, were divided into groups; above (spinal cord injury - high, n = 8) and below (spinal cord injury - low, n = 7) T6 level. On separate days, VO2peak was compared between: (i) ACE, (ii) FES iso hybrid, and (iii) FES hybrid cycling.

RESULTS

In the SCI-high group, FES iso hybrid increased VO2peak (17.6 (standard deviation (SD) 5.0) to 23.6 (SD 3.6) ml/kg/min; p = 0.001) and ventilation (50.4 (SD 20.8) to 58.2 (SD 20.7) l/min; p = 0.034) more than ACE. Furthermore, FES hybrid cycling resulted in a 6.8 ml/kg/min higher VO2peak (p = 0.001) and an 11.0 litres/minute (p = 0.001) higher ventilation. ACE peak workload was 10.5 W (p = 0.001) higher during FES hybrid cycling compared with ACE. In the spinal cord injury - low group, no significant differences were found between the modalities.

CONCLUSION

VO2peak increased when ACE was combined with FES iso hybrid or FES hybrid cycling in persons with spinal cord injury above the T6 level. Portable FES may serve as a less resource-demanding alternative to stationary FES cycling, and may have important implications for exercise prescription for spinal cord injury.

Disc height and sagittal alignment in operated and non-operated levels in the lumbar spine at long-term follow-up: a case-control study

Purpose:

To compare lumbar disc degeneration at 9-year follow-up in patients with chronic low back pain who had instrumented lumbar fusion or no fusion.

Material and methodology:

The main outcomes were disc height and sagittal alignment measured by Distortion Compensated Roentgen Analysis (DCRA). Secondary outcome included the Oswestry Disability Index and VAS back pain.

Results:

Forty-eight patients with baseline and 9-year radiographs from L2- S1 were included. Twenty-three had lumbar fusion and 25 had no fusion. Disc height was reduced at all levels independent of fusion. No difference in disc height and sagittal alignment was observed between patients fused and not fused. There were weak correlations, ranging from 0.04 to 0.36, between clinical and radiological parameters.

Conclusion:

Lumbar disc degeneration increased at all measured levels independent of fusion and correlated poorly with clinical outcome.

Comparison of the SF6D, the EQ5D, and the oswestry disability index in patients with chronic low back pain and degenerative disc disease

Background

The need for cost effectiveness analyses in randomized controlled trials that compare treatment options is increasing. The selection of the optimal utility measure is important, and a central question is whether the two most commonly used indexes - the EuroQuol 5D (EQ5D) and the Short Form 6D (SF6D) – can be used interchangeably. The aim of the present study was to compare change scores of the EQ5D and SF6D utility indexes in terms of some important measurement properties. The psychometric properties of the two utility indexes were compared to a disease-specific instrument, the Oswestry Disability Index (ODI), in the setting of a randomized controlled trial for degenerative disc disease.

Methods

In a randomized controlled multicentre trial, 172 patients who had experienced low back pain for an average of 6 years were randomized to either treatment with an intensive back rehabilitation program or surgery to insert disc prostheses. Patients filled out the ODI, EQ5D, and SF-36 at baseline and two-year follow up. The utility indexes was compared with respect to measurement error, structural validity, criterion validity, responsiveness, and interpretability according to the COSMIN taxonomy.

Results

At follow up, 113 patients had change score values for all three instruments. The SF6D had better similarity with the disease-specific instrument (ODI) regarding sensitivity, specificity, and responsiveness. Measurement error was lower for the SF6D (0.056) compared to the EQ5D (0.155). The minimal important change score value was 0.031 for SF6D and 0.173 for EQ5D. The minimal detectable change score value at a 95% confidence level were 0.157 for SF6D and 0.429 for EQ5D, and the difference in mean change score values (SD) between them was 0.23 (0.29) and so exceeded the clinical significant change score value for both instruments. Analysis of psychometric properties indicated that the indexes are unidimensional when considered separately, but that they do not exactly measure the same underlying construct.

Conclusions

This study indicates that the difference in important measurement properties between EQ5D and SF6D is too large to consider them interchangeable. Since the similarity with the “gold standard” (the disease-specific instrument) was quite different, this could indicate that the choice of index should be determined by the diagnosis.

Segmental mobility, disc height and patient-reported outcomes after surgery for degenerative disc disease

This prospective multicentre study was undertaken to determine segmental movement, disc height and sagittal alignment after total disc replacement (TDR) in the lumbosacral spine and to assess the correlation of biomechanical properties to clinical outcomes.

A total of 173 patients with degenerative disc disease and low back pain for more than one year were randomised to receive either TDR or multidisciplinary rehabilitation (MDR). Segmental movement in the sagittal plane and disc height were measured using distortion compensated roentgen analysis (DCRA) comparing radiographs in active flexion and extension. Correlation analysis between the range of movement or disc height and patient-reported outcomes was performed in both groups. After two years, no significant change in movement in the sagittal plane was found in segments with TDR or between the two treatment groups. It remained the same or increased slightly in untreated segments in the TDR group and in this group there was a significant increase in disc height in the operated segments. There was no correlation between segmental movement or disc height and patient-reported outcomes in either group.

In this study, insertion of an intervertebral disc prosthesis TDR did not increase movement in the sagittal plane and segmental movement did not correlate with patient-reported outcomes. This suggests that in the lumbar spine the movement preserving properties of TDR are not major determinants of clinical outcomes.

Cite this article: Bone Joint J 2013;95-B:81–9.

Effect of leg vascular occlusion on arm cycling peak oxygen uptake in spinal cord-injured individuals

STUDY DESIGN

Cross-sectional single-subject design.

OBJECTIVES

To determine whether leg vascular occlusion (LEVO) augment arm cycling (ACE) peak oxygen uptake in spinal cord-injured individuals.

SETTING

University Hospital, Norway.

METHODS

Fifteen individuals with C(4) to T(12) spinal cord injury (SCI) were recruited and divided into two groups: injury above (SCI-high, n=8) or below (SCI-low, n=7) the T(6) level. Peak oxygen uptake (VO(2peak)) was measured during (1) ACE combined with LEVO, (2) ACE alone and (3) ACE combined with functional electrical stimulation cycling (FES hybrid cycling).

RESULTS

In the SCI-high group, VO(2peak) and peak Watt during ACE with LEVO were higher than ACE alone: 20.0 (±5.0) versus 17.6 (±5.0) ml kg(-1) min(-1) (P=0.006), and 72.5(±32) versus 80.0 (±34) Watt (P=0.016), respectively. However, FES hybrid cycling VO(2peak) was significantly higher than ACE with LEVO: 24.4 (±4.1) versus 20.0 (±5.0) ml kg(-1) min(-1) (P=0.006). In the SCI-low group, there was no difference in VO(2peak) and related parameters between the three modalities.

CONCLUSIONS

For spinal cord-injured individuals with injury level above T(6) (high) in the present study, LEVO combined with ACE augment VO(2peak). However, this acute increase in VO(2peak) was lower than when FES cycling was combined with ACE. These findings may have future implications for exercise prescription for spinal cord-injured individuals.

Disc height and motion patterns in the lumbar spine in patients operated with total disc replacement or fusion for discogenic back pain. Results from a randomized controlled trial

BACKGROUND CONTEXT

Fusion is considered the "gold standard" in surgical treatment of degenerated disc disease; the intended postoperative goal is absence of mobility, but treatment may induce degeneration in adjacent segments. Total disc replacement (TDR) aims to restore and maintain mobility by replacing a painful disc. Little is known about the degree and quality of mobility in artificial discs in vivo and whether maintained mobility reduces the stress on adjacent segments that is believed to occur after fusion.

PURPOSE

To see if surgical goals for respective treatments had been reached, if clinical outcome was related to this, and if differences in disc height at treated segments and adjacent segment motion patterns between groups occurred.

STUDY DESIGN

Comparison of X-ray measurements in a randomized controlled trial between instrumented posterior fusion and TDR for chronic low back pain (CLBP) assumed to be discogenic. Results were compared with clinical outcome.

PATIENT SAMPLE

The material consisted of 152 patients suffering from CLBP assumed to be discogenic. Seventy-two patients were treated with fusion and 80 with TDR.

OUTCOME MEASURES

Results of X-ray measurements were compared between groups and related to self-reported clinical results regarding back pain and disability.

METHODS

Flexion-extension X-rays were analyzed preoperatively and 2 years postoperatively using distortion-compensated Roentgen analysis (DCRA) at treated and adjacent levels, and mobility after fusion and TDR was estimated. Changes in disc height and range of motion (ROM) respective translation in adjacent segments were compared between groups. Results of DCRA measurements were also compared with the clinical outcome.

RESULTS

Preoperative flexion-extension ROM was similar between the fusion and TDR groups, and preoperative disc heights of segments to be treated were between one and two standard deviation less than that previously established in a normative database. Seventy percent of fused patients had no mobility, whereas 85% of TDR patients were mobile. Fulfillment of surgical goals was correlated to neither back pain nor disability. Fused segments were lower and TDR segments were higher than normative values postoperatively. There were also significant differences at adjacent segments, there being more translation and flexion-extension in the fusion group than in the TDR group.

CONCLUSIONS

This very accurate X-ray method (DCRA) indicates that surgical goals were reached in most patients. This, however, was not correlated to clinical outcome. Differences between the groups in postoperative disc height at treated segments, respective ROM, and translation at adjacent segments did not affect the clinical outcome after 2 years.

Psychosocial interventions as part of breast cancer rehabilitation programs? Results from a systematic review

OBJECTIVE

This systematic review aimed to determine the effectiveness of psychoeducation, cognitive behavioural therapy (CBT) and social support interventions used in the rehabilitation of breast cancer (BC) patients.

METHODS

We conducted a systematic literature search to identify randomised controlled trials of female BC patients who underwent different psychosocial interventions during or after primary cancer treatment. The methodological quality of all studies was independently assessed by two reviewers. Studies with low quality, less than 20 participants in each group, patients with metastatic cancer, data not presented separately for BC and studies that included other cancer types were excluded.

RESULTS

Among 9617 identified studies, only 18 RCTs published between 1999 and 2008, including 3272 patients were finally included in this systematic evaluation. Outcome measures were categorised into quality of life (QoL), fatigue, mood, health behaviour and social function. Six trials examined psychoeducation had inconsistent results, both during and after the primary treatment. Seven trials examined the effect of CBT, four of which given after primary treatment (range 6-12 weeks) demonstrated improvements in QoL; the other three CBT studies given during primary treatment (range 9-20 weeks) had inconsistencies. Five studies addressed social support and showed no conclusive impacts of this intervention.

CONCLUSIONS

Limited documentation exists on the efficacy of psychosocial rehabilitation interventions among BC patients. However, we found that patients might have QoL benefits from CBT given after primary BC treatment. More documentation is needed regarding the effects of CBT during primary treatment and the effects of psychoeducation and social support.

Segmental motion adjacent to anterior cervical arthrodesis: a prospective study

STUDY DESIGN

Prospective, observational study.

OBJECTIVE

The present study describes in a prospective setting the kinematics changes occurring at segments adjacent to a one-level cervical arthrodesis.

SUMMARY OF BACKGROUND DATA

The development of adjacent segment disease has been noticed by many clinicians. Whether symptoms develop due to fusion induced accelerated spondylosis or due to a natural development in a predisposed person is currently under debate. The motivation for introducing motion preservation procedures in the neck is primarily to protect the patients from developing symptomatic adjacent disc disease. To accept this rationale, it has to be demonstrated that a fusion creates an unfavorable biomechanical situation at adjacent levels.

METHODS

Forty-six patients underwent standard anterior cervical decompression and fusion using a cylindrical cage implant. Lateral radiographic views of the cervical spine in flexion and extension were obtained before surgery, and at 12 months of follow-up. Employing Distortion Compensated Roentgen Analysis, rotational and translational motion at adjacent levels was quantified prospectively.

RESULTS

Rotational and translational motion at adjacent cranial and caudal levels did not exhibit a significant change between the preoperative state and the state 12 months after the operation.

CONCLUSION

The assumption of an iatrogenically caused increased mobility by a one-level cervical fusion could not be confirmed 12 months after surgery.

Force and stiffness of the pelvic floor as function of muscle length: A comparison between women with and without stress urinary incontinence

AIMS

To compare passive and active mechanical properties in the pelvic floor as a function of tissue length in continent and incontinent parous women.

MATERIALS AND METHODS

Twenty-four parous continent and 21 parous incontinent women were examined with an intravaginal device. Passive and active force/stiffness were measured by increasing the transverse diameter of the vagina. To allow a more accurate comparison between groups, measured forces were normalized with respect to bodyweight, that is, force/bodyweight.

RESULTS

In both groups passive and active forces increased as a function of the increase in length of the pelvic floor tissues. No difference was found between the groups according to passive forces (P = 0.646), but active force was significantly higher (P = 0.030) in the continent group when normalized for bodyweight. There was an almost linear increase in normalized passive stiffness in the range tested. No differences were found between the groups (P = 0.855). Normalized active stiffness was significantly reduced in the incontinent group (P = 0.021).

CONCLUSIONS

This study indicates that both active force development and active stiffness in the pelvic floor tissues are significantly reduced in incontinent women, whereas the passive resting mechanical forces in the pelvic floor tissues in both groups are not different.

Mobility of lumbar segments instrumented with a ProDisc II prosthesis: a two-year follow-up study

STUDY DESIGN

Longitudinal prospective study on a sample of 41 consecutive disc prosthesis patients, covering a postoperative time period of at least 2 years.

OBJECTIVES

To document the rotational and translational range of segmental motion of patients instrumented with ProDisc II prostheses in the lumbar spine and to compare motion between instrumented and untreated adjacent segments with respect to a normative database. To discuss potential causes of the low range of rotational motion observed after instrumentation with a Prodisc II prosthesis.

SUMMARY OF BACKGROUND DATA

Disc replacement is intended to restore physiologic motion and height of the affected levels. Published reports show, however, that the goal of restoring motion at the operated segment is missed in the majority of cases. The cause of this failure is unresolved.

METHODS

Rotational and translational segmental motion in the sagittal plane, disc height, and posteroanterior displacement were measured from lateral radiographic views taken standing (before surgery) and in flexion and extension (1 year and 2 years after surgery) by Distortion Compensated Roentgen Analysis (DCRA). The protocol permits to take measurements from all segments imaged on the radiographic views and compensates for variations in stature, magnification, and posture. Data from instrumented and untreated segments can be compared and related to a previously determined normative database.

RESULTS

The rotational range of motion of segments instrumented with a ProDisc II prosthesis was low, especially at L4-L5 and L5-S1. In the majority of cases, it amounted to less than 45% of the normal range. Virtually no improvement occurred between 1 and 2 years after surgery. Malalignment of the axis of rotation of the prosthesis with respect to the anatomic axis, persisting clinical symptoms, or the significant increase of intervertebral space documented after instrumentation are unlikely to cause the low range of motion. As the range of rotational motion of the untreated segments was low with respect to normal as well, it is conjectured that tissue adaptation during the preoperative symptomatic time period might have caused the postoperative motion deficit. This conjecture complies with fragmentary previous observations of a low postoperative segmental range of motion from untreated segments of fusion patients.

CONCLUSIONS

Disc replacement in the lumbar spine by a ProDisc II implant fails to restore normal segmental rotational motion in the sagittal plane, specifically at levels L4-L5 and L5-S1. As segmental motion of the untreated segments was lower than normal as well, though not quite as conspicuous as that of instrumented segments, adaptation of soft tissue taken place during the preoperative symptomatic time period is conjectured to cause the observed motion deficit. Postoperative physical therapy might be considered if restoration of a normal range of rotational motion is desired.

Transforaminal steroid injections in the treatment of cervical radiculopathy. A prospective outcome study

BACKGROUND

The aim of this study was to assess if transforaminal steroid injections applied to cohort of patients waiting for cervical disc surgery, reduce the pain of cervical radiculopathy and hence reduce the need for surgical intervention. Cervical radiculopathy due to cervical disc herniation or spondylosis is a common indication for cervical disc surgery. Surgery is however not always successful, and is not done without risk of complications. Transforaminal injection of steroids has gained popularity due to the rationale that inflammation of the spinal nerve roots causes radicular pain, and therefore steroids placed locally should relieve symptoms.

METHODS

During a 12-month period, 21 secondary referral patients with unilateral cervical radiculopathy entered the study. Cervical disc herniation or spondylosis affecting the corresponding nerve root was demonstrated by appropriate investigation (MRI or myelography). The patients then received 2 transforaminal steroid injections, at 2 weeks interval, while waiting for operative treatment. The pain intensity (VAS), Odom's criteria and operative indications were registered at 6 weeks and 4 months.

FINDINGS

After receiving injection treatment 5 of the 21 patients decided to cancel the operation due to clinical improvement. A statistically significant reduction (0.02) in radicular pain score was simultaneously measured. This corresponds well with the reduction in operative requirements since radicular pain is the main indication for operative treatment. The responders experienced a long-lasting effect. Those responding positively however improved neck pain to the same extent as radicular pain, and patients with cervical spondylosis responded as positively as those with disc herniation.

INTERPRETATION

This prospective cohort study indicates a reduction in the need for operative treatment due to injection treatment. The clinical effect is measurable, and a statistically significant improvement of the radicular pain is registered. Routine transforaminal injection treatment prior to surgery seems rewarding, but the complication risk must be taken into consideration.

Comparing precision of distortion-compensated and stereophotogrammetric Roentgen analysis when monitoring fusion in the cervical spine

Two methods to measure sagittal plane segmental motion in the cervical spine are compared. Translational and rotational motion was measured in nine cervical motion segments of nine patients by distortion-compensated (DCRA) as well as by stereophotogrammetric Roentgen analysis (RSA). To compare measurement precision of the new DCRA protocol with the established RSA technique under realistic clinical conditions and to discuss advantages and disadvantages of both methods in clinical studies. RSA constitutes the most precise method available to assess segmental motion or to monitor fusion in the cervical spine. Due to the invasive nature of the procedure there is an interest in alternative, non-invasive protocols, based on conventional, lateral radiographic views. In nine patients, segmental motion of nine cervical segments with spinal surgery and fusion had previously been assessed from stereo views by RSA. From the archive radiographs, sagittal plane segmental motion was re-assessed by DCRA. Results for sagittal plane translational and rotational motion obtained by both methods are compared. With respect to RSA, sagittal plane rotation was determined by DCRA with an error of 2.4 degrees and a mean difference not significantly different from zero. Sagittal plane translation was determined by DCRA with an error of less than 0.78 mm and a mean difference not significantly different from zero. As two methods are compared, these errors represent the combined (propagated) errors of RSA and DCRA. Averaged over the cohort investigated, measurement of sagittal plane segmental motion exhibited no significant difference between DCRA and RSA.

Degeneration and height of cervical discs classified from MRI compared with precise height measurements from radiographs

STUDY DESIGN

Descriptive study comparing MRI classifications with measurements from radiographs.

OBJECTIVES

1. Define the relationship between MRI classified cervical disc degeneration and objectively measured disc height. 2. Assess the level of inter- and intra-observer errors using MRI in defining cervical disc degeneration.

SUMMARY OF BACKGROUND DATA

Cervical spine degeneration has been defined radiologically by loss of disc height, decreased disc and bone marrow signal intensity and disc protrusion/herniation on MRI. The intra- and inter-observer error using MRI in defining cervical degeneration influences data interpretation. Few previous studies have addressed this source of error. The relation and time sequence between cervical disc degeneration classified by MRI and cervical disc height decrease measured from radiographs is unclear.

METHODS

The MRI classification of degeneration was based on nucleus signal, prolaps identification and bone marrow signal. Two neuro-radiologists evaluated the MR-images independently in a blinded fashion. The radiographic disc height measurements were done by a new computer-assisted method compensating for image distortion and permitting comparison with normal level-, age- and gender-appropriate disc height.

RESULTS/CONCLUSIONS

1. Progressing disc degeneration classified from MRI is on average significantly associated with a decrease of disc height as measured from radiographs. Within each MRI defined category of degeneration measured disc heights, however, scatter in a wide range. 2. The inter-observer agreement between two neuro-radiologists in both defining degeneration and disc height by MRI was only moderate. Studies addressing questions related to cervical disc degeneration should take this into consideration.

Congenital cervical block vertebrae are associated with caudally adjacent discs

BACKGROUND

Knowledge on the time course of changes in cervical disc height and cervical kinematics at motion segments adjacent to congenital block vertebrae is fragmentary. Compared with this, after surgical fusion of cervical spine segments some find increased degenerative processes in combination with hypermobility or instability while others were unable to confirm these changes. This cross sectional study was undertaken to investigate whether congenital block vertebrae are associated with an increased risk of disc degeneration and hypermobility at adjacent motion segments.

METHODS

In 25 subjects (mean age 40 years) disc height, vertebral height and segmental mobility at motion segments adjacent to a congenital block vertebra were assessed quantitatively by distortion-compensated Roentgen analysis. The findings were compared to a normal database.

FINDINGS

Height of the disc cranially adjacent to the block vertebra did not deviate from the norm while height of the caudally adjacent disc was significantly reduced. The height of the vertebrae adjacent to the block did not deviate from normal. The motion segments formed by the block vertebra and the adjacent discs and vertebrae exhibited no deviation from normal with respect to sagittal plane rotational or translational motion.

INTERPRETATION

Congenital block vertebrae do not result in rotational or translational hyper- or hypomobility at motion segments adjacent to the block. Whether the observed, significant height reduction of the caudally adjacent disc is caused by degeneration following the block formation cannot undoubtedly be concluded as the initial state is not known. Further longitudinal studies are needed to investigate this issue.

Force-length relationship in the pelvic floor muscles under transverse vaginal distension: a method study in healthy women

AIMS

The purpose of this study was to investigate whether there is a relationship between changes in the diameter of the urogenital hiatus and force developed in pelvic floor musculature. In addition, we wanted to examine the reliability of the method that measures force development in the pelvic floor in the transverse direction of the urogenital hiatus.

MATERIALS AND METHODS

Passive and total force in the pelvic floor was measured with an intra-vaginal device in 20 healthy parous volunteers. The measurements were done with a consecutively increasing diameter in the transverse plane of the urogenital hiatus. The procedure was repeated with a few days interval.

RESULTS

The measurements show an increase in force with an increasing device-diameter. The results are reliable at all the diameters tested, estimated by the within-subject day-to-day variability which was non-significant. The 40 mm diameter device is most favourable, estimated by Bland Altman plots of the test-retest measurements.

CONCLUSIONS

Force development in pelvic floor muscles increased as a function of vaginal diameter when measured in the frontal plane. The measurements were reliable at all the different diameters chosen.

Are fatigue and disturbances in pre-programmed activity of pelvic floor muscles associated with female stress urinary incontinence?

AIMS

To investigate whether there is a difference between a continent versus a stress urinary incontinent group of women regarding: (i) fatigue in pelvic floor muscles, and (ii) pre-activation times between pelvic floor and abdominal muscles during coughing.

METHODS

Twenty-six continent and 20 stress urinary incontinent parous women were examined. Fatigue was measured with an intravaginal device. Time to 10% decline of the initial reference force (RF) was defined as time-to-fatigue. Simultaneous recordings of force developed in levator ani muscle and electromyographic activity in the external oblique abdominal muscle were performed to determine whether contraction of pelvic floor muscles precedes activity in abdominal muscles during coughing.

RESULTS

Time-to-fatigue was identical in the two groups (10.5 sec in the continent and 11.5 sec in the incontinent group, median values). Normalized force was significantly reduced in the incontinent group. The pelvic floor muscles contracted 160 msec before the abdominal muscles in both groups. In 24% of the continent and in 30% of the incontinent women, however, abdominal muscle activity preceded activity of pelvic floor muscles.

CONCLUSIONS

Muscular fatigue, defined as rate of force loss, does not seem to be associated with urinary stress incontinence. Moreover, muscular activity recruitment patterns were equal in both groups suggesting that other factors than disturbances of ordered muscle recruitment, that is, pelvic floor followed by abdominal muscles, may be responsible for stress urinary incontinence. It is likely that reduced normalized force, as found in the incontinent group, is an important contributing factor.

Increased sagittal plane segmental motion in the lower cervical spine in women with chronic whiplash-associated disorders, grades I-II: a case-control study using a new measurement protocol

STUDY DESIGN

Case-control study comparing sagittal plane segmental motion in women (n = 34) with chronic whiplash-associated disorders, Grades I-II, with women (n = 35) with chronic insidious onset neck pain and with a normal database of sagittal plane rotational and translational motion.

OBJECTIVE

To reveal whether women with chronic whiplash-associated disorders, Grades I-II, demonstrate evidence of abnormal segmental motions in the cervical spine.

SUMMARY OF BACKGROUND DATA

It is hypothesized that unphysiological spinal motion experienced during an automobile accident may result in a persistent disturbance of segmental motion. It is not known whether patients with chronic whiplash-associated disorders differ from patients with chronic insidious onset neck pain with respect to segmental mobility.

METHODS

Lateral radiographic views were taken in assisted maximal flexion and extension. A new measurement protocol determined rotational and translational motions of segments C3-C4 and C5-C6 with high precision. Segmental motion was compared with normal data as well as among groups.

RESULTS

In the whiplash-associated disorders group, the C3-C4 and C4-C5 segments showed significantly increased rotational motions. Translational motions within each segment revealed a significant deviation from normal at the C3-C4 segment in the whiplash-associated disorders and insidious onset neck pain groups and at the C5-C6 segment in the whiplash-associated disorders group. Significantly more women in the whiplash-associated disorders group (35.3%) had abnormal increased segmental motions compared to the insidious onset neck pain group (8.6%) when both the rotational and the translational parameters were analyzed. When the translational parameter was analyzed separately, no significant difference was found between groups, or 17.6% (whiplash-associated disorders group) and 8.6% (insidious onset neck pain group), respectively.

CONCLUSION

Hypermobility in the lower cervical spine segments in 12 out of 34 patients with chronic whiplash-associated disorders in this study point to injury caused by the accident. This subgroup, identified by the new radiographic protocol, might need a specific therapeutic intervention.

Vertebral height, disc height, posteroanterior displacement and dens-atlas gap in the cervical spine: precision measurement protocol and normal data

OBJECTIVE

(1) Precise measurement of vertebral height, disc height, posteroanterior displacement and dens-atlas gap from lateral radiographic views of the cervical spine. (2) Compilation of a normative database for these parameters, specifying dependence on gender and age.

DESIGN

Descriptive study, based on measurements from lateral radiographic views of the cervical spine of healthy subjects.

BACKGROUND

Normal data of vertebral height, disc height, posteroanterior displacement and size of the dens-atlas gap as well as their biological range of variation and potential dependence on gender and age are not available.

METHODS

Based on computer-aided measurements from lateral radiographic views of the cervical spine, a new protocol determines these parameters.

RESULTS

are compensated for radiographic magnification, variation in stature and the individually adopted posture of the cervical spine; they are virtually uninfluenced by radiographic distortion and patient alignment errors. A specimen study as well as inter- and intra-observer studies quantify measurement errors.Results. Employing the new protocol, vertebral height C3-C7 and disc height C2/C3-C6/C7 are measured with relative errors of 3.9% and 5.7% respectively. Posteroanterior displacement C1/C2 to C6/C7 is measured with an error of 2.8% of mean vertebral depth and the dens-atlas gap is measured with an error of <1.8% of the depth of C2. A normal database for the dimensions of cervical vertebrae and discs as well as of the sagittal plane alignment of the vertebrae within the cervical spine is compiled from 135 lateral views of healthy adults.

CONCLUSIONS

Vertebral height, disc height, posteroanterior displacement and size of the dens-atlas gap are measured with high precision. Normal data are presented for the first time.

RELEVANCE

The new protocol in conjunction with the normal database enables future studies detecting or monitoring morphological effects of, for example, trauma, long-term high mechanical loading, disc degeneration, rheumatoid arthritis, fusion or other surgical interventions.

Sagittal plane segmental motion of the cervical spine. A new precision measurement protocol and normal motion data of healthy adults

OBJECTIVE

(1) Precise documentation of sagittal plane segmental rotational and posteroanterior translational motion of segments C0/C1-C6/C7 of the human cervical spine from lateral radiographic views. (2) Compilation of a database describing normal motion. (3) Comparison of individual motion patterns with the normal database.

DESIGN

Descriptive study based on computer-aided measurements from lateral radiographic views taken in flexion and extension.

BACKGROUND

Previous studies concentrated on segmental rotational motion of the cervical spine. Normal data for translational motion were not available. Description of cervical spine motion patterns thus remained incomplete.

METHODS

Based on computer-aided measurements from lateral radiographic views taken in flexion and extension, a new protocol determines rotational and translational motion for all segments (C0/C1-C6/C7) imaged on the radiographic views. Measured results are corrected for radiographic magnification and variation in stature; they are virtually uninfluenced by radiographic distortion and patient alignment errors. A database describing normal motion was compiled from 137 sets of lateral views of healthy adults taken in active flexion and extension. A specimen study as well as inter- and intra-observer studies quantify measurement errors.

RESULTS

The error study demonstrated the error (SD) of a rotational motion measurement to amount to slightly less than 2 degrees. The error (SD) of a translational motion measurement amounts to less than 5% of vertebral depth; for a vertebra of 15 mm depth this corresponds to 0.7 mm. A normal database for rotational and translational motion was compiled. There was a linear relation between rotational and translational motion. This finding agrees qualitatively with results from previous studies; quantitative comparisons are not possible due to divergent definitions for translational motion. The relation between rotation and translation can be employed in individual cases to predict translational motion, in dependence on the rotation actually performed. A comparison of the rotational motion with the normal database and the difference between predicted and actual translational motion allow segmental hypo-, normal or hypermobility to be quantified.

CONCLUSIONS

The new protocol measures segmental motion with high precision and corrects for radiographic distortion, variation in stature and alignment errors of patients. Thus, archive studies using existing radiographs are feasible.

RELEVANCE

Flexion-extension radiographs of the cervical spine are performed to explore potential damage to the bony or ligamentous structure resulting in abnormal, segmental motion patterns. Determining rotational motion gives only an incomplete picture. The new protocol allows for precise quantification of translational motion and classification of segments as hypo- or hypermobile by comparison with normal motion data.

Do human lumbar discs reconstitute after chemonucleolysis? A 7-year follow-up study

STUDY DESIGN

A retrospective, longitudinal study of 51 patients, covering a mean follow-up period of 81 months.

OBJECTIVE

To observe the long-term temporal course of the height of human lumbar discs after chemonucleolysis. To document whether human lumbar discs reconstitute, thus characterizing the healing potential of central disc tissue.

SUMMARY OF BACKGROUND DATA

Although reconstitution of disc height within some months of chemonucleolysis has been observed in animal experiments, human lumbar discs have shown no tendency to regain their initial height within 1 year of treatment. To date, there has been no report on longer follow-up periods. The different reactions of animal and human discs may be dose-related or related to differences in tissue properties, physiologic environment or in vivo loading conditions.

METHODS

Using a new protocol, the heights of lumbar discs were measured from sets of lateral radiographic views of 51 patients subject to chemonucleolysis by treatment with chymopapain (doses of 4000 or 3000 picokatals [pkat]). The sets comprised a view taken before treatment, a view taken (on average) 4 months after treatment, and a view taken (on average) 81 months after treatment. In the majority of patients, untreated discs adjacent to discs treated with chemonucleolysis served as control discs.

RESULTS

Shortly after injection of chymopapain, all treated discs decreased in height. The height decrease of treated discs amounted to 15.8% on average. In the subcohort treated with 4000 pkat, the loss did not reverse during the entire follow-up period; in the subcohort treated with 3000 pkat a small fraction of the lost height was regained. Untreated neighboring control discs showed a minor (3.4%) decrease in height.

CONCLUSIONS

Human lumbar discs do not reconstitute after chemonucleolysis. Because the long-term temporal course of disc height in patients is in disagreement with observations from animal experiments, caution is suggested when generalizing results from animal studies to humans.

Assessment of sagittal plane segmental motion in the lumbar spine. A comparison between distortion-compensated and stereophotogrammetric roentgen analysis

STUDY DESIGN

Sagittal plane translatory and rotatory motion was measured in 15 lumbar motion segments of 8 patients by distortion-compensated and stereophotogrammetric Roentgen analysis.

OBJECTIVE

To compare measurement precision of the new distortion-compensated Roentgen analysis protocol with that of the established Roentgen stereophotogrammetric technique under realistic clinical conditions.

SUMMARY OF BACKGROUND DATA

Roentgen stereophotogrammetric analysis constitutes the most precise method available to assess segmental motion. Because of the invasive nature of the procedure, however, there is interest in alternative, noninvasive protocols suitable for studying larger patient cohorts.

METHODS

In 8 patients, segmental motion of 15 lumbar segments that had undergone previous spinal surgery was assessed from stereo views by using Roentgen stereophotogrammetric analysis. Sagittal plane segmental motion was assessed by distortion-compensated Roentgen analysis. Sagittal plane translatory and rotatory motion data obtained by both methods were compared.

RESULTS

With respect to Roentgen stereophotogrammetric analysis, sagittal plane rotation was determined by distortion-compensated Roentgen analysis with an error (standard deviation) of 1.4 degrees and a mean difference of less than 0.05 degree. Sagittal plane translation was determined by distortion-compensated Roentgen analysis, with an error of 1.25 mm and a mean difference 0.5 mm.

CONCLUSION

Measurement precision of distortion-compensated Roentgen analysis is slightly inferior to that of Roentgen stereophotogrammetric analysis but substantially higher than that of conventional protocols assessing lumbar segmental motion. If measurement precision is considered adequate and if a noninvasive technique is indicated, distortion-compensated Roentgen analysis can be used to provide reliable motion data required for epidemiologic and clinical studies.

Spinal shrinkage during work in a sitting posture compared to work in a standing posture

OBJECTIVE: The objective was to measure the possible differences in shrinkage of the thoracolumbar spine in subjects working in a sitting and a standing posture for 6.5 h at work, in a realistic work environment. The isolated shrinkage of the thoracic and the lumbar spine was also examined. STUDY DESIGN: This study presents a new protocol to measure shrinkage of the thoracic and lumbar spine separately. BACKGROUND: Controversies still exist with regard to the load on the spine in a sitting compared to a standing position. Some report that shrinkage is greatest in the sitting position while others report the reverse. However, nothing is known about the height reduction of the thoracic and the lumbar spine during loading for 6.5 h in a real work environment. Therefore, the behaviour of the thoracic and the lumbar spine under practical condition has to be investigated. METHOD: A stadiometer with a measurement error of 0.51 mm was used to measure changes in spinal height during work. To exclude first-time behaviour of the spine, a pre-test lasting 50 min was undertaken. The mean of the last three measurements was used as the reference height. During work, height measurements of the spine were performed every 20 min. To separate the behaviour of the thoracic and the lumbar spine, two benchmarks were placed at the vertebrae prominens and at the thoracic-lumbar junction. Shrinkage of the spine was investigated within three different cohorts: (I) work in a sitting posture for 6.5 h; (II) relaxed sitting for 2 h vs work for 2 h in a sitting position and (III) work in a standing position for 6.5 h. RESULTS: Relaxed sitting leads to a gain in stature compared to work in a sitting position for 2 h. The major gain in stature occurred in the lumbar spine. Comparison of cohort (III) working in a standing position with cohort (I) working in a sitting position shows that the shrinkage of the spine is greatest when work is performed in a standing posture. The major differences were found in the shrinkage of the lumbar spine, e.g. shrinkage of the lumbar spine in the standing cohort (III) was 4.16 mm compared to 1.73 mm in the sitting cohort (I). CONCLUSIONS: There is a gain in stature during relaxed sitting compared to work in a sitting posture. The load on the spine is greatest when work in a standing position is performed. The greater shrinkage of the lumbar spine during work in a standing position compared to a sitting posture is probably due to: (i) differences in lumbar lordosis and (ii) the effect of bending and torsion while handling the work materials.

Precision measurement of segmental motion from flexion-extension radiographs of the lumbar spine

OBJECTIVE: To measure sagittal plane motion of lumbar vertebrae from lateral radiographic views. Previously identified factors of imprecision such as distortion in central projection, off-centre position, axial rotation, and lateral tilt of the spine were compensated. STUDY DESIGN: This study presents a new protocol to measure sagittal plane rotational and translational motion from lateral flexion-extension radiographs of the lumbar spine. BACKGROUND: Conventional methods to determine sagittal plane rotation and translation are prone to error from the distortional effects of the divergence of the radiographic beam and the measurement error inherent in constructing tangents to the contours of the vertebral body. High precision is attained by roentgen-stereophotogrammetric methods, but because of their invasive nature they can be applied only in exceptional cases. Agreement has been reached only in that measurement of sagittal plane motion from lumbar spine flexion-extension radiographs is inaccurate. Normal patterns of sagittal plane motion and the definition of what is an abnormal flexion-extension radiograph have not been settled. METHOD: Starting from an analysis of vertebral contours in the lateral view, geometric measures are identified which are virtually independent of distortion, axial rotation or lateral tilt. Applying a new protocol based on those geometric measures, the pattern of translational and rotational motion was determined from flexion-extension radiographs of 61 symptom-free, adult subjects. Measurement errors were quantified in a specimen experiment; a reproducibility study quantified inter- and intraobserver errors. RESULTS: Magnitude and sign of 'translation per degree of rotation' determined from a cohort of 61 adult subjects were very uniform for all levels of the lumbar spine. An auxiliary study evaluating a cohort of 10 healthy subjects where flexion-extension radiographs had been taken standing and side-lying showed no dependence of the rotation/translation pattern on posture. The error study demonstrated errors in angle ranging between 0.7 and 1.6 degrees and errors in displacement ranging between 1.2% and 2.4% of vertebral depth (the largest errors occurring at the L(5)/S(1) segment). Intra- and interobserver tests showed no or only negligibly small bias and an SD virtually equal to the measurement error multiplied by radical2. The relation of displacement to angle observed in the normal cohort can be used in individual cases to predict translational motion depending on the rotation actually performed. A comparison of the predicted translation (determined from normal controls) and the value actually measured allows translational hypo-, normal, or hypermobility to be quantified. Examples illustrate application of the new method in cases of normal, hypo-, and hypermobility and in the case of an instrumented spine. CONCLUSIONS: The results of this study show that precision of the measurement of rotational and translational motion can be considerably enhanced by making allowance for radiographic distortional effects and by minimizing subjective influence in the measurement procedure.

Mechano-reception in osteoblast-like cells

Response to mechanical stimulation is a basic biological phenomenon. Nearly all cells process mechanical input and respond to it by inducing and modulating biochemical pathways. In organisms with tissues, if the average mechanical load is increased, some tissues can increase their performance and often increase their bulk by cell division. A reduction in mechanical loading decreases performance, catabolic activity gains, and the tissue degenerates. The process of anabolism and catabolism regulated by mechanical loading is a second-to-second, minute-to-minute, and hour-to-hour process that works together with local and systemic hormones to ensure that the tissue can meet the demands of the mechanical environment. On the other hand, a mechanical load that is too high can cause tissue and matrix failure and damage to the cells, which can result in inflammation. In this paper, we review the possible biophysical and cell biological mechanisms that might be responsible for transducing physiological and hyperphysiological mechanical loading into the biological response of skeletal cells. We speculate on what the mechanism of mechano-transduction in bone might be compared with that of other cells and on how information produced by mechanical loading might be passed on to other cells to achieve a coordinated tissue response.

Changes in muscle fiber cross-sectional area and concentrations of Na,K-ATPase in deltoid muscle in patients with impingement syndrome of the shoulder

Disturbances of the stabilizing musculature are an important factor in painful shoulders. The important changes in the rotator cuff muscles are well established, but less attention is put on possible disturbances of the deltoid muscle. This study investigated the effect of shoulder impingement on muscle fiber cross-sectional area and the Na,K-pump concentration of the deltoid muscle. The study included six patients with impingement syndrome. Biopsies were taken from the affected and unaffected sides. The muscle fiber cross-sectional area and the Na,K-ATPase concentration was measured. There were significant decreases (p < 0.05) in cross-sectional area of type 1 and type 2 fibers of the affected deltoid muscle of 25 and 18%, respectively. The Na,K-pump concentration of the affected muscles was reduced by 26.6% (p < 0.05).

Thigh muscle atrophy after femoral shortening. Vastus intermedius cross-section studied in osteotomized rats

We determined the effect of a shortening/lengthening osteotomy on muscle fiber cross-sectional area in the vastus intermedius in 14 rats. The left femur was shortened 5 mm in half of the rats and elongated 5 mm in the other half. In both groups, the right femur was osteotomized and stabilized without shortening/lengthening. After 3 months, open biopsy specimens of the vastus intermedius were taken for measurements of the muscle cross-sectional area in both Type 1 and Type 2 fibers; 150 fibers were measured in each specimen. In the shortened group, the cross-section was reduced in both types of fibers. After lengthening, no differences in the fiber cross-sectional area were found. We conclude that differences in stretch and tension of the muscles are responsible for the atrophy after femoral shortening and the maintenance of the fiber cross-sectional area after lengthening.

Effects of reduced joint mobility and training on Na,K-ATPase and Ca-ATPase in skeletal muscle

In guinea pigs, the ankle joint was partly immobilized in a position reducing dorsiflection to 105 degrees (as compared to the normal value of 30 degrees). When compared with the contralateral unrestrained leg, this led to a significant atrophy and a decrease in contractile force (-23%) of the gastrocnemius muscle. This was associated with a significant decrease in the total concentration of [3H]ouabain binding sites in gastrocnemius and plantaris muscle reaching minimum (-19% and -23%) after 3 weeks, but no evidence of degenerative changes. Total contents of Ca and Ca-ATPase were increased by 27% and 22%, respectively. After 4 to 5 weeks of reduced mobility, the concentration of [3H]ouabain binding sites in gastrocnemius muscle returned to control level. The lowest concentration of [3H]ouabain binding sites reached during reduced mobility was 258 +/- 13 pmol/g wet wt., and the maximum value attained following 3 weeks of reduced mobility and 3 weeks of training by running was 498 +/- 25 pmol/g wet wt., i.e, 93% higher. In soleus, training produced an increase of 25%. Clinically, it is important to realize that movable braces cannot prevent the development of muscular atrophy. The observed spontaneous recovery of the Na,K-pump concentration may partly explain why patients using movable casts show a better capacity for physical performance than those treated with complete immobilization. In conclusion, the total concentration of Na,K-pumps in guinea pig skeletal muscle undergoes downregulation and upregulation as a function of contractile activity as well as muscle length under conditions mimicking the constraints on mobility frequently used in the clinical treatment of lesions.