Do patients with ankylosing spondylitis have poorer balance than normal subjects?

Use of posturography in patients with ankylosing spondylitis: A systematic review

Background

Ankylosing spondylitis (AS) is characterised as a chronic inflammatory disease of the axial skeleton. The force platform is an option for performing the postural assessment of these individuals.

Objectives

To review and evaluate the behaviour of the centre of pressure (CoP) variables during the postural control examination in patients with AS compared to a control group.

Method

A systematic review, registered in PROSPERO, that followed the PRISMA Statement. A search was carried out in the following databases: Medline, Web of Science, Embase, Scopus, and Scielo, from 1945 to 2023. Studies were selected that aimed to understand the use of the force platform for the assessment of postural control. The risk of bias assessment was performed using the AXIS tool.

Results

Five studies were included, with a total of 247 participants. The assessment of risk of bias presented high scores in the AXIS tool. Patients with a diagnosis of AS presented increased thoracic kyphosis in most of the studies, as well as large displacements in the anteroposterior (AP) and mediolateral (ML) directions, and altered total mean velocity (TMV) and frequency, indicating worse postural stability. Regarding the functional status, the most used questionnaires were the Bath Ankylosing Spondylitis Functional Index (BASFI), Bath Ankylosing Spondylitis Metrology Index (BASMI) and Bath Ankylosing Disease Activity Index (BASDAI).

Conclusion

Patients with ankylosing spondylitis present postural instability, verified by means of higher values of centre of posture variables.

Clinical implications

Individuals with ankylosing spondylitis presented postural instability and balance deficit. Therefore, exercises for balance training and postural control are essential in the clinical management of these patients.

The relationship of cervicothoracic mobility restrictions to fall risk and fear of falling in ankylosing spondylitis

Objective

The objective of this study is to determine whether restricted cervical mobility in ankylosing spondylitis (AS) is associated with increased fall frequency or fear of falling.

Methods

A total of 134 AS patients and 199 age- and gender-matched control subjects (CS) with soft-tissue cervicothoracic pain were prospectively evaluated for fall risk. Subjects were divided into non-fallers, single fallers, and multiple fallers. Dynamic cervical rotations and static cervicothoracic axial measurements were compared between the groups. In total, 88 AS patients were reviewed more than once; Kaplan-Meier plots were constructed for fall risk as a function of cervical rotation amplitudes. Falls Efficacy Scale-International (FES-I) questionnaire measured the fear of falling.

Results

In total, 34% of AS patients and 29% of CS fell (p = 0.271) in the year prior to evaluation. In AS, static anatomical measurements were unrelated to fall occurrence. The trends of multiple AS fallers to greater flexed forward postures and reduced dynamic cervical rotations were not statistically significant. Cervicothoracic pain (p = 0.0459), BASDAI (p = 0.002), and BASFI (p = 0.003) scores were greater in multiple fallers. FES-I scores were greater in fallers (p = 0.004). Of the 88 AS patients reviewed (or seen) on more than one occasion, 46.5% fell over the 9-year observation period, including all multiple fallers and 71.4% of single fallers. Survival curves showed increased fall risk as cervical rotational amplitudes decreased.

Conclusion

In AS, decreased cervical rotations increase fall risk and fear of falling. In multiple fallers, falls were associated with greater disease activity. Cervical muscle stiffness in AS may cause non-veridical proprioceptive inputs and contribute to increased fall frequency similar to individuals with soft-tissue cervicothoracic pain.

Comparison of the effects of aerobic training alone versus aerobic training combined with clinical Pilates exercises on the functional and psychosocial status of patients with ankylosing spondylitis: A randomized controlled trial

To compare the effects of aerobic training versus aerobic training combined with clinical Pilates exercises (CPE) on the functional and psychosocial status of patients with ankylosing spondylitis (AS). Twenty-eight patients with ankylosing spondylitis (AS) were randomized into 2 groups. Group 1 (n = 14) performed both aerobic training and CPE, whereas group 2 (n = 14) performed aerobic training alone. Functional status of the patients was assessed using the Bath Ankylosing Mobility Index (BASMI), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Functional Index (BASFI), back scratch test (BST), single leg stance test, functional reach test, a dynamometer, chair sit and stand test, and 6-minute walk test (6MWT), and the psychosocial status of the patients was assessed using the Ankylosing Spondylitis Quality of Life (ASQoL) questionnaire, the Multidimensional Assessment of Fatigue (MAF), Pittsburgh Sleep Quality Index (PSQI), Hospital Anxiety Depression Scale (HADS), and Tampa Scale of Kinesiophobia (TSK). Both training programs were conducted for 8 weeks, and then, the assessments were repeated. A statistically significant improvement was observed in the BASMI (p = .001), BASDAI (p = .001), BASFI (p = .002), BST (right, p = .05; left, p = .025), functional reach test (p = .013), back muscle strength (p = .033), 6MWT (p = .011), ASQoL (p < .001), MAF (p = .01), and PSQI (p = .013) scores in group 1. A significant difference was observed in the BASDAI (p = .028), chair sit and stand test (p = .022), 6MWT (p = .04), and ASQoL (p = .04) scores in group 2. CPE in addition to aerobic training was more effective in improving the functional and psychosocial status of the patients with AS.

Ankylosing Spondylitis and the Risk of Hip Fractures: a Matched Cohort Study

BACKGROUNDS

It has been hypothesized that ankylosing spondylitis is associated with an increased risk of incident hip fractures due to osteoporosis and risk of falls but the supporting evidence is limited and mixed.

OBJECTIVES

To assess the risk of hip fractures in a large cohort of patients with ankylosing spondylitis compared to a matched cohort.

DESIGN

A retrospective cohort study.

SUBJECTS

Men and women diagnosed with ankylosing spondylitis from 1 January 2002 to 31 December 2018. Matching in a 5:1 ratio was based on age and sex. Follow-up ended on 23 June 2019.

MAIN MEASURES

Cox regression models adjusting for confounders defined in a causal inference framework were used to determine the hazard ratio for hip fractures.

KEY RESULT

The final cohorts included 5,909 ankylosing spondylitis patients and 28,671 matched patients. The ankylosing spondylitis cohort had a mean age of 49 (17) years and was composed of 3,762 (64%) men, 3,638 (62%) patients born in Israel, and 1,532 (26%) patients of low residential socioeconomic status. During 45,388 and 224,192 cumulative person-years of follow-up, the ankylosing spondylitis and matched cohorts had 2.47 and 1.63 cases of hip fractures per 1,000 person-years, respectively. Ankylosing spondylitis patients also developed hip fractures earlier (74 [13] vs. 79 [10] years, p = 0.002). Ankylosing spondylitis was associated with hip fractures in the unadjusted (HR = 1.52, 95% CI [1.23-1.88]) and adjusted (HR = 1.56, 95% CI [1.27-1.93]) models. The association was evident in men (HR = 1.65, 95% CI [1.25-2.18]) and women (HR = 1.48, 95% CI [1.07-2.05]).

CONCLUSION

This study found that ankylosing spondylitis patients developed hip fractures earlier and more often compared to a matched cohort. This study suggests that ankylosing spondylitis patients might benefit from more proactive screening, mitigation, and prevention of risk factors for hip fractures.

Management of spine fractures in ankylosing spondylitis and diffuse idiopathic skeletal hyperostosis: a challenge

OBJECTIVE

Ankylosing spinal disorders (ASDs) such as ankylosing spondylitis (AS) and diffuse idiopathic skeletal hyperostosis (DISH) are complex diseases regarding diagnostics, treatment, and patient outcome, especially in trauma. Originating from rigid biomechanics and low bone quality in considerably comorbid patients, serious spinal injury requires thorough and immediate imaging and is frequently missed. The aim of this study was to evaluate patient characteristics as well as procedures in patients with ASD in order to identify the major particularities of treatment.

METHODS

A total of 60 patients aged 78.5 ± 8.9 years were retrospectively included. Preoperative imaging as well as surgical treatment procedures and postoperative patient outcome were analyzed, including 30-day readmissions.

RESULTS

CT imaging of the entire spine was performed within 24 hours after the initial trauma in 73.3% of patients. A delay in diagnostics (> 24 hours) occurred in 41.7% of patients transferred from primary care centers. At admission, 25.0% of patients had fracture-related neurological deficits (American Spinal Injury Association [ASIA] grades A and B in 4 patients, and ASIA grades C and D in 11 patients). A spinal epidural hematoma was found in 21.2% of patients and was symptomatic in 72.7% of those patients. Of the patients with fracture-related neurological deficits, 93.3% were operated on within 48 hours from symptom onset. One patient (1.7%) developed neurological deficits from diagnosis to surgery. Postoperatively, 18.3% of patients had surgical complications, and 76.7% of patients developed further medical issues, with pneumonia (38.3%), pulmonary decompensation (25.0%), and cardiac decompensation (20.0%) being the leading causes. The 30-day mortality rate was high at 10.0%.

CONCLUSIONS

Treatment of patients with ASDs is complex. While surgical outcome is usually good, the multimorbid nature of these patients results in a high rate of major medical complications. If an ankylosing disease is suspected, MRI of the entire spine is mandatory. Upon diagnosis, treatment should be performed in centers capable of managing all aspects of the regular complications these patients will develop.

The effects of head posture on nerve conduction studies in patients with ankylosing spondylitis

Ankylosing spondylitis (AS) is a chronic inflammatory disease which effects cervical posture of patients. The aim of this study was to evaluate AS patients according to the degree of cervical disorder and was evaluate them electrophysiologically, functionality, and disease parameters. Our study comprised 64 AS patients and 30 healthy controls. The head posture of patients was evaluated by craniovertebral angle (CVA) measurement. Nerve conduction of bilateral median, radial, ulnar, and medial antebrachial cutaneous (MAC) nerves were studied in all patients. The most important nerve conduction differences in AS patients who have severe forward head posture (FHP) were decrease in sensory nerve action potential (SNAP) amplitude and compound muscle action potential amplitudes of median nerves, a decrease in the SNAP amplitude of ulnar nerves, a delay in the F response latency of ulnar nerves, and prolongation in the SNAP latency of the MAC nerve. The FHP disorder that develops in AS patients may have electro physiological effects, similar to those of thoracic outlet syndrome In addition, the functional status of these patients is worsened as severity of FHP increases.

Sagittal spinal alignment in patients with ankylosing spondylitis by rasterstereographic back shape analysis: an observational retrospective study

BACKGROUND

Ankylosing spondylitis (AS) is a chronic-inflammatory disorder involving the sacroiliac-joints, spine, and spinal ligaments. A proper understanding of the sagittal plane alignment and posture is essential in managing deformities of the spine.

AIM

The aim of this study was to evaluate the differences in sagittal plane alignment between patients with AS and healthy subjects by means of rasterstereography and to analyze the relationship between clinical assessments and postural features.

DESIGN

Observational retrospective study.

SETTING

This study took place from January 2012 to April 2014 at the rheumatologic out-patient clinic, Umberto I Hospital, Rome, Italy.

POPULATION

Forty-six healthy subjects and twenty-five AS patients were enrolled in the study.

METHODS

Spinal posture was measured by the rasterstereographic system Formetric 4D. Trunk inclination, kyphosis angle, lordosis angle, cervical and lumbar plumbline distance, and sagittal pelvic alignment were analyzed. Differences between the two groups in postural parameters were compared (primary outcomes). Multiple regression analysis was used to evaluate if postural parameters could be predicted by the Bath Ankylosing Spondylitis Metrology Index (BASMI) that is a composite index of spinal mobility, disease duration and body mass index (secondary outcomes).

RESULTS

Patients with AS showed a significant increase in the kyphosis angle and the cervical plumbline distance and a significant reduction in the lordosis angle and the sagittal pelvic alignment when compared to healthy subjects. According to multiple regression analysis, BASMI influenced the kyphosis angle value with a standardized coefficient β of 1.93, the lordosis-angle value with a standardized coefficient β of -2.79 and sagittal pelvic alignment value with a standardized coefficient-β of -2.93.

CONCLUSIONS

Rasterstereography has proved to be a valid tool in monitoring change in spinal structure in AS patients and has shown a strong correlation with clinimetric parameters of AS (BASMI). Future studies are needed, with a greater number of patients, in order to better characterize the evidently existing relationship between postural changes in AS patients and rasterstereography.

CLINICAL REHABILITATION IMPACT

Rasterstereography has proved to be a valid tool in monitoring postural changes in AS patients and has shown a strong correlation with clinical evaluations. Therefore, the assessment of postural characteristics using the rasterstereographic system before and after a specific exercise program would be a reliable and valid advice without exposing subjects to high doses of radiations.

Magnetic resonance tomography for the early detection of occult fractures of the spinal column in patients with ankylosing spondylitis

Purpose

The purpose of this study was to determine the extent to which magnetic resonance imaging (MRI) performed in patients with ankylosing spondylitis (AS) after low- and no-energy trauma leads to an improved diagnosis and, as a result, to a change in the therapeutic strategy.

Methods

All patients with AS, who underwent surgery after minor traumas (low-energy traumas, LETs) and patients without trauma history (NET: no-energy trauma), were retrospectively analysed. The diagnostic and planned surgical procedure was examined initially and again after total spine MRI in patients with persistent and/or new complaints.

Results

One hundred and thirty-six patients with AS after trauma were surgically treated. A total of 92 patients with LETs and 12 patients with NETs were included. After initial diagnostics (CT and X-ray) were performed in 15.4% of the patients with LET or NET (n = 16), we found occult fractures on MRI scans. In ten of these patients (6 LET, 4 NET) in which a previous decision was made to follow conservative therapy, no fracture indication was found on CT or X-ray. Two fracture heights were observed in six patients who experienced LET. However, on X-ray and CT, the fractures were only visible at one height. All fractures were treated surgically with stabilization and decompression if indicated.

Conclusion

Considering the high percentage of our patient population with occult fractures, we recommend supplementing the basic diagnostic procedures with an MRI of the entire spinal column in patients with painful spinal column findings after minor trauma and for those with persistent pain without trauma.

Graphic abstract

These slides can be retrieved under Electronic Supplementary Material.

Retrospective evaluation of pregnancies with ankylosing spondylitis in a tertiary center in Turkey

BACKGROUND

To evaluate obstetrical and perinatal outcomes of pregnancies with ankylosing spondylitis (AS).

METHODS

This was a retrospective study evaluating obstetric outcomes of 52 patients with AS who were followed up at our institution between 2006 and 2019. Patients were classified as having disease greater than or less than 5 years, and according to disease-related medical treatment during pregnancy, as drug free, single medication or multiple medication.

RESULTS

Overall rates of preterm delivery, intrauterine growth retardation and preeclampsia were 17.3%, 13.4% and 7.7%, respectively. Thirty-three of the patients were followed up without any medication, while 19 patients used drugs during pregnancy. Seven patients used a single drug and 12 patients had multiple drugs. There was no significant difference in terms of obstetrical and neonatal outcomes. However, a higher rate of neonatal intensive care unit (NICU) admission was observed in the group using medication for AS, despite a lack of statistical significance (31.5% vs 15%, P = .162). On the other hand, patients having disease more than 5 years had higher rates of Apgar scores less than <7 and admission to the NICU despite a lack of statistical significance (4% vs 7.4% and 16% vs 26%; P = .267 and P = .297, respectively).

CONCLUSION

In conclusion, pregnancies of patients with AS must be considered as high risk due to increased rates of adverse outcomes such as preterm delivery, intrauterine growth retardation or preeclampsia.

Core stability and balance in patients with ankylosing spondylitis

The main purpose of this study was to compare core stability and balance between ankylosing spondylitis (AS) patients and healthy controls. AS patients diagnosed according to the Modified New York criteria and healthy age- and sex-matched controls were included in the study. Clinical status of AS patients was assessed using Bath AS Disease Activity Index (BASDAI), Bath AS Functional Index (BASFI), Bath AS Spinal Mobility Index (BASMI). For evaluation of core stability, static and dynamic core endurance and hip strength were assessed. Trunk flexor and extensor endurance, lateral side bridge tests for static core endurance; modified sit-up test for dynamic core endurance were used. Hip strength was measured with a hand-held dynamometer. Biodex Balance System was used to assess static and dynamic balance. Bilateral standing static and dynamic postural stability, single leg standing postural stability and limits of stability test results were recorded. 64 AS patients (40 male, 24 female) and 64 healthy controls (39 male, 25 female) were assessed. Static and dynamic core endurance test results, hip abductor strength were significantly higher in control group than AS group (p < 0.05). Static postural stability and left leg postural stability test results were significantly better in control group than AS group (p < 0.05). Overall, forward, backward, and right, limits of stability test results were significantly higher in control group (p < 0.05). The results of our study demonstrate that AS has negative effects on core stability and balance. It would be beneficial to add core stability and balance training to AS patients' rehabilitation program.

Spine Fractures in Ankylosing Diseases: Recommendations of the Spine Section of the German Society for Orthopaedics and Trauma (DGOU)

STUDY DESIGN

Review of literature and case series.

OBJECTIVES

Update and review of current treatment concepts for spine fractures in patients with ankylosing spinal disorders.

METHODS

Case presentation and description of a diagnostic and therapeutic algorithm for unstable spinal injuries with an underlying ankylosing spinal disorder (ASD) of the cervical and thoracolumbar spine.

RESULTS

Nondisplaced fractures can be missed easily using conventional X-rays. Thus, computed tomography (CT) scans are recommended for all trauma patients with ASD. In doubt or presence of any neurologic involvement additional magnetic resonance imaging (MRI) scans should be obtained. Spine precautions should be maintained all times and until definitive treatment (<24 h). Nonoperative fracture treatment is not recommended given the mechanical instability of the most commonly seen fracture patterns (AOSpine B- and C-type, M2) in patients with ASD and inherent high risk of secondary neurologic deterioration. For patients with ankylosing spondylitis (AS) or diffuse idiopathic hyperostosis (DISH) sustaining cervical spine fractures, a combined anterior-posterior instrumentation for fracture fixation is recommended. Closed reduction and patient positioning can be challenging in presence of preexisting kyphotic deformities. In the thoracolumbar (TL) spine, a posterior instrumentation extending 2 to 3 levels above and below the fracture level is recommended to maintain adequate reduction and stability until fracture healing. Minimally invasive percutaneous pedicle screws and cement augmentation can help to minimize the surgical trauma and strengthen the construct stability in patients with diminished minor bone quality (osteopenia, osteoporosis).

CONCLUSIONS

Current concepts, treatment options, and recommendations of the German Orthopedic Trauma Society-Spine Section for spinal fractures in the ankylosed spine have been outlined.

Managing morbidity and treatment-related toxicity in patients with ankylosing spondylitis

AS is the prototypical member of the family of spondyloarthropathies, and is characterized by seronegativity, axial predominance and new bone formation, which underlie symptoms of inflammatory back pain, enthesopathy and extra-articular manifestations, including anterior uveitis, psoriasis and colitis. Patients with AS typically experience a wide variety of morbidities. These include both morbidities related to the disease itself—most prominently progressive, irreversible, structural damage to the axial or peripheral skeleton—and morbidities stemming from treatments for the disease, including toxicities from NSAID use, and increased risk of infections and immunogenicity concerns with biologics. AS is also associated with a number of comorbidities. We review the risks associated with AS, its comorbidities and its treatments, as well as strategies that can be used to mitigate these risks in patients with AS.

[Becoming older with axial spondyloarthritis]

The combination of physiological age-related changes (e. g. reduction in muscle mass and function, reduction in organ function and degenerative changes in joints) and disease-specific changes of ankylosing spondylitis (AS), make older AS patients vulnerable for additional diseases. In this patient population various processes lead to a reduction in physical function, changes in posture, osteoporosis and sarcopenia, which then can result in falls and fractures, especially vertebral fractures. Mortality is increased in patients with AS, particularly in men due to an increase in cardiovascular mortality. Although the standardized assessment of cardiovascular risk factors in patients with inflammatory rheumatic diseases (independent of age) has been recommended for years, it is rarely done in clinical practice. Overall, data on comorbidities and risk factors are only available for AS patients and are lacking for other forms of spondyloarthritides.

Ankylosing Spondylitis and Balance

Ankylosing spondylitis is a chronic inflammatory disease that mainly affects axial joints and the changes in the vertebrae cause typical kyphotic posture. In patients with ankylosing spondylitis, the postural changes, including cervical flexion, decreased lumbar lordosis, posterior rotation of pelvis, hip extension, knee flexion, and plantar flexion of ankle along with kyphosis, may occur in the upcoming terms of the disease and may negatively affect balance. Joint and eye involvements; muscular, vestibular and proprioceptional changes can also affect balance. This review evaluates the ankylosing spondylitis-equilibrium relationship together with posture and other parameters of balance.

What Impairs Balance in Ankylosing Spondylitis? Posture or Disease Activity?

Objectives

Objectives: This study aims to compare ankylosing spondylitis (AS) patients with healthy subjects in terms of posture and balance, and to identify the factors correlated with balance in AS.

Patients and methods

Thirty patients (17 males, 13 females; mean age 41.7±7.7 years; range 31 to 57 years) with AS and 33 healthy subjects (18 males, 15 females; mean age 41.3±7.0 years; range 26 to 56 years) were included in the study. Participants were assessed in terms of posture and balance. Posture was assessed using tragus-wall distance, modified Schober's test, and chest expansion. Balance was assessed using device-assisted balance tests. Pain (visual analog scale) and disease activity (Bath Ankylosing Spondylitis Disease Activity Index) were assessed only in AS patients.

Results

Ankylosing spondylitis patients walked more slowly when compared to healthy subjects (p=0.002). As the modified Schober's test was restricted, AS patients had greater step width in tandem walk and higher sway velocity on foam base (r=-0.418 p=0.022; r=-0.473 p=0.008). Neither Bath Ankylosing Spondylitis Disease Activity Index nor visual analog scale was correlated with balance.

Conclusion

Static and dynamic balance are impaired in AS patients when compared to healthy subjects. Restricted mobility of the spine and advanced kyphosis impaired balance, while pain and disease activity had no correlations with balance.

Clinical outcomes following spinal fracture in patients with ankylosing spondylitis

BACKGROUND

Ankylosing spondylitis is a seronegative rheumatoid condition mainly affecting the axial skeleton. It leads to progressive deformity and stiffening of the spine with an increased risk of vertebral fractures and significant neurological deficits compared to the general population.

AIM

This study aimed to evaluate the outcomes of patients with ankylosing spondylitis who sustained acute vertebral fractures over a 10-year period.

METHODS

A retrospective review of patient records and radiographic images was performed. Mechanism of injury, fracture type, timing of diagnosis, neurological deficit, management and complications were assessed.

RESULTS

Twenty-four patients were included. Most (23) sustained low energy injuries. Five (20%) patients had a delayed diagnosis over 24 h after the time of injury. Twelve (50%) of patients had a neurological deficit at the time of admission and most did not recover. Eighteen (75%) patients underwent surgical stabilisation. There were 19 complications (in 15 patients) following surgery.

CONCLUSION

Patients with ankylosing spondylitis are at risk of spinal fracture and associated spinal cord injury after relatively minor trauma. Delayed diagnosis places the patient at risk of neurological compromise, and thus a high index of suspicion is needed when assessing this patient group.

Postural deformities: potential morbidities to cause balance problems in patients with ankylosing spondylitis?

OBJECTIVE

This study aimed to assess the impact of postural deformities caused by ankylosing spondylitis (AS) on balance problems.

MATERIAL AND METHODS

This study included 29 patients with AS and 21 healthy controls. For assessing exercise capacity and dynamic balance, timed up and go test, five times sit-to-stand test, gait speed, and 6-min walk test were performed. Romberg tests were used to evaluate static balance and proprioception, whereas Dynamic Gait Index (DGI), Functional Gait Assessment (FGA), Berg Balance Scale (BBS), Activity Specific Balance Confidence Scale (ABC), Dizziness Handicap Inventory (DHI), and functional reach test were used to assess dynamic balance and the risk of falling. Using Bath Ankylosing Spondylitis Metrology Index (BASMI) scores, patients with AS were divided into two groups: those with scores 0-4 were assigned to subgroup AS1, and those with scores 5-10 were assigned to subgroup AS2.

RESULTS

In the whole group of patients with AS, five times sit-to-stand test, tandem Romberg test with eyes closed, and BBS and ABC scores were significantly worse than the healthy controls (p<0.05). In the AS2 subgroup having more severe and advanced disease, five additional parameters, including timed up and go test, 6-min walk test, functional reach test, FGA, and DHI scores were also significantly worse than the healthy controls (p<0.05). Comparing the two subgroups with each other, only BBS scores were significantly worse in the AS2 subgroup than in the AS1 subgroup.

CONCLUSION

Although in clinical practice, poor balance is not a common problem in AS, possibly because of compensatory mechanisms, patients with AS have poorer static and dynamic balance than healthy subjects. Significantly worse BBS scores in the AS2 subgroup than in the AS1 subgroup may suggest the presence of more dynamic balance problems in advanced disease; however, future studies comprising larger samples are necessary to confirm this assumption.

Spinal fractures in patients with ankylosing spondylitis

The ankylosed spine is prone to fracture even after minor trauma due to its changed biomechanical properties. The two central features of ankylosing spondylitis (AS) that promote the pathological remodeling of the spine are inflammation and new bone formation. AS is also associated with osteoporosis that is attributed to an uncoupling of the bone formation and bone resorption processes. Therefore, bone resorption occurs and promotes weakening of the spine as well as increased risk of vertebral fractures which can be hugely different in terms of clinical relevance. Even in the presence of symptomatic clinical vertebral fractures, the diagnosis can be overruled by attributing the pain to disease activity. Furthermore, given the highly abnormal structure of the spine, vertebral fracture diagnosis can be difficult on the basis of radiography alone. CT can show the fractures in detail. Magnetic resonance imaging is considered the method of choice for the imaging of spinal cord injuries, and a reasonable option for exclusion of occult fractures undetected by CT. Since it is equally important for radiologists and clinicians to have a common knowledge base rather than a compartmentalized view, the aim of this review article was to provide the required clinical knowledge that radiologists need to know and the relevant radiological semiotics that clinicians require in diagnosing clinically significant injury to the ankylosed spine.

Time-dependent changes in postural control in early Parkinson's disease: what are we missing?

Impaired postural control (PC) is an important feature of Parkinson's disease (PD), but optimal testing protocols are yet to be established. Accelerometer-based monitors provide objective measures of PC. We characterised time-dependent changes in PC in people with PD and controls during standing, and identified outcomes most sensitive to pathology. Thirty-one controls and 26 PD patients were recruited: PC was measured with an accelerometer on the lower back for 2 minutes (mins). Preliminary analysis (autocorrelation) that showed 2 seconds (s) was the shortest duration sensitive to changes in the signal; time series analysis of a range of PC outcomes was undertaken using consecutive 2-s windows over the test. Piecewise linear regression was used to fit the time series data during the first 30 s and the subsequent 90 s of the trial. PC outcomes changed over the 2 mins, with the greatest change observed during the first 30 s after which PC stabilised. Changes in PC were reduced in PD compared to controls, and Jerk was found to be discriminative of pathology. Previous studies focusing on average performance over the duration of a test may miss time-dependent differences. Evaluation of time-dependent change may provide useful insights into PC in PD and effectiveness of intervention.

Ankylosing spondylitis and posture control: the role of visual input

Objectives. To assess the motor control during quiet stance in patients with established ankylosing spondylitis (AS) and to evaluate the effect of visual input on the maintenance of a quiet posture. Methods. 12 male AS patients (mean age 50.1 ± 13.2 years) and 12 matched healthy subjects performed 2 sessions of 3 trials in quiet stance, with eyes open (EO) and with eyes closed (EC) on a baropodometric platform. The oscillation of the centre of feet pressure (CoP) was acquired. Indices of stability and balance control were assessed by the sway path (SP) of the CoP, the frequency bandwidth (FB1) that includes the 80% of the area under the amplitude spectrum, the mean amplitude of the peaks (MP) of the sway density curve (SDC), and the mean distance (MD) between 2 peaks of the SDC. Results. In severe AS patients, the MD between two peaks of the SDC and the SP of the center of feet pressure were significantly higher than controls during both EO and EC conditions. The MP was significantly reduced just on EC. Conclusions. Ankylosing spondylitis exerts negative effect on postural stability, not compensable by visual inputs. Our findings may be useful in the rehabilitative management of the increased risk of falling in AS.

Neuropathic pain in ankylosing spondylitis: a psychophysics and brain imaging study

OBJECTIVE

To determine whether there is a neuropathic component in ankylosing spondylitis (AS) back pain and to delineate gray matter brain abnormalities associated with AS.

METHODS

Seventeen patients with back pain secondary to AS who were not receiving biologic agents and 17 age- and sex-matched healthy controls consented to participate in the study and were assessed using the painDETECT instrument (scores of ≤12 indicating low probability of neuropathic pain) and the McGill Pain Questionnaire. Mechanical and thermal thresholds were determined in all subjects, and brain gray matter was assessed by 3T magnetic resonance imaging.

RESULTS

Eleven of the 17 AS patients had painDETECT scores of >12. The patients had decreased mechanical and cold sensitivity on the dorsum of their feet but did not have altered pain thresholds. Compared to controls, the AS patients exhibited cortical thinning in the primary somatosensory, insular, anterior cingulate, and anterior mid-cingulate cortices and the supplemental motor area, and increased gray matter volume in the thalamus and putamen. Scores on the painDETECT in AS patients were correlated with decreased gray matter in the primary somatosensory cortex and with increased gray matter in the motor cortex, anterior cingulate cortex, prefrontal cortex, thalamus, and striatum.

CONCLUSION

The present findings indicate that neuropathic pain occurs in AS. Furthermore, abnormal brain gray matter and neural correlates of neuropathic pain are concordant with the clinical picture of AS, which includes sensorimotor and mood deficits as well as neuropathic pain symptoms. These results suggest that back pain in AS is a mixed pain condition that includes a neuropathic pain component.

Biomechanical assessment of balance and posture in subjects with ankylosing spondylitis

Background

Ankylosing spondylitis is a major chronic rheumatic disease that predominantly affects axial joints, determining a rigid spine from the occiput to the sacrum. The dorsal hyperkyphosis may induce the patients to stand in a stooped position with consequent restriction in patients’ daily living activities. The aim of this study was to develop a method for quantitatively and objectively assessing both balance and posture and their mutual relationship in ankylosing spondylitis subjects.

Methods

The data of 12 healthy and 12 ankylosing spondylitis subjects (treated with anti-TNF-α stabilized), with a mean age of 51.42 and 49.42 years; mean BMI of 23.08 and 25.44 kg/m² were collected. Subjects underwent a morphological examination of the spinal mobility by means of a pocket compass needle goniometer, together with an evaluation of both spinal and hip mobility (Bath Ankylosing Spondylitis Metrology Index), and disease activity (Bath Ankylosing Spondylitis Disease Activity Index). Quantitative evaluation of kinematics and balance were performed through a six cameras stereophotogrammetric system and a force plate. Kinematic models together with a test for evaluating balance in different eye level conditions were developed. Head protrusion, trunk flexion-extension, pelvic tilt, hip-knee-ankle flexion-extension were evaluated during Romberg Test, together with centre of pressure parameters.

Results

Each subject was able to accomplish the required task. Subjects’ were comparable for demographic parameters. A significant increment was observed in ankylosing spondylitis subjects for knee joint angle with the target placed at each eye level on both sides (p < 0.042). When considering the pelvic tilt angle a statistically significant reduction was found with the target placed respectively at 10° (p = 0.034) and at 30° (p = 0.019) less than eye level. Furthermore in ankylosing spondylitis subjects both hip (p = 0.048) and ankle (p = 0.029) joints angles differs significantly. When considering the posturographic parameters significant differences were observed for ellipse, center of pressure path and mean velocity (p < 0.04). Goniometric evaluation revealed significant increment of thoracic kyphosis reduction of cervical and lumbar range of motion compared to healthy subjects.

Conclusions

Our findings confirm the need to investigate both balance and posture in ankylosing spondylitis subjects. This methodology could help clinicians to plan rehabilitation treatments.

Postural control is altered in patients with ankylosing spondylitis

BACKGROUND

Ankylosing spondylitis is a chronic inflammatory disorder that can lead to increased axial and peripheral joint stiffness, impairing joint mobility. Impaired axial mobility due to vertebral ankylosis may result in changes in standing postural control. Little research has addressed changes in standing postural control in the ankylosing spondylitis population, nor how these issues might affect clinical understanding and treatment.

METHODS

Sixteen ankylosing spondylitis patients, and 17 healthy controls participated. Each individual completed two 120-second quiet standing trials with eyes open and eyes closed, while standing upon two force platforms. Net center of pressure displacement and mean power frequency in the frontal and sagittal planes were calculated. A Spearman's rank correlation analysis was performed between net center of pressure measures and several clinical measures of disease activity.

FINDINGS

Frontal plane net center of pressure displacement and frequency content, and sagittal plane net center of pressure displacement were significantly greater within the ankylosing spondylitis patient group. Ankylosing spondylitis patients demonstrated a significant increase in frontal plane net center of pressure displacement in the eyes-closed condition. Net center of pressure displacement and frequency were significantly correlated to the Bath Ankylosing Spondylitis Functional Index, and individual components of the Bath Ankylosing Spondylitis Metrology Index.

INTERPRETATION

Quiet standing postural control was altered particularly so in the frontal plane in patients with ankylosing spondylitis, which may be associated with increased fall risk. Posturographic measures of postural control may serve as valuable clinical tools for the monitoring of disease progression and disease status in ankylosing spondylitis.

Physical fitness in patients with ankylosing spondylitis: comparison with population controls

BACKGROUND

Although flexibility traditionally has been the main focus for physical therapy in patients with ankylosing spondylitis (AS), there is now evidence for an increased risk of cardiovascular diseases (CVDs) in this group.

OBJECTIVE

The purposes of this study were: (1) to compare physical fitness (cardiorespiratory fitness, muscular capacity, flexibility, and balance) in patients with AS and controls and (2) to explore associations between physical fitness and disease activity in the patient group.

DESIGN

This was a cross-sectional study.

METHODS

The physical fitness variables were cardiorespiratory fitness (treadmill test for estimation of peak oxygen uptake [V(O(2))peak]), muscular capacity (push-ups test), balance (30-second single-leg stand and walking in a figure-of-eight pattern), and flexibility (Bath Ankylosing Spondylitis Metrology Index [BASMI]). The Ankylosing Spondylitis Disease Activity Score (ASDAS) was used to assess disease activity. Group differences and associations were tested with the chi-square test for categorical variables, the Mann-Whitney U test for ordinal variables, and analysis of covariance for continuous variables.

RESULTS

One hundred forty-nine of 250 of the invited patients with AS and 133 of 329 of the invited controls were included in the study. The mean ASDAS score of the patient group was 2.3 (range=0.5-4.7), and the median disease duration was 23 years (range=7-55). The patient group had significantly lower V(O(2)) peak values, with a mean difference of -2.7 mL·kg(-1)·min(-1) (95% confidence interval=-4.3, -1.1), and higher BASMI scores, with a mean difference of 1.6 (95% confidence interval=1.5, 1.8), compared with the control group. No group differences were found in balance or muscular capacity. In the patient group, significant inverse associations were found between ASDAS scores and V(O(2))peak and muscular capacity.

LIMITATIONS

The response rate was lower in the control group (40.4%) than in the patient group (59.6%).

CONCLUSION

The lower cardiorespiratory fitness and reduced flexibility in the AS group indicate that physical therapy programs should include cardiorespiratory fitness exercises as a basic component to reduce the risk of cardiovascular disease.

Impaired gait in ankylosing spondylitis

Ankylosing spondylitis (AS) is a chronic, inflammatory rheumatic disease. The spine becomes rigid from the occiput to the sacrum, leading to a stooped position. This study aims at evaluating AS subjects gait alterations. Twenty-four subjects were evaluated: 12 normal and 12 pathologic in stabilized anti-TNF-alpha treatment (mean age 49.42 (10.47), 25.44 (3.19) and mean body mass index 55.75 (3.19), 23.73 (2.7), respectively). Physical examination and gait analysis were performed. A motion capture system synchronized with two force plates was used. Three-dimensional kinematics and kinetics of trunk, pelvis, hip, knee and ankle were determined during gait. A trend towards reduction was found in gait velocity and stride length. Gait analysis results showed statistically significant alterations in the sagittal plane at each joint for AS patients (P < 0.049). Hip and knee joint extension moments showed a statistically significant reduction (P < 0.044). At the ankle joint, a decreased plantarflexion was assessed (P < 0.048) together with the absence of the heel rocker. Gait analysis, through gait alterations identification, allowed planning-specific rehabilitation intervention aimed to prevent patients' stiffness together with improve balance and avoid muscles' fatigue.

Spinal cord injury in patients with ankylosing spondylitis: a 10-year review

STUDY DESIGN

Retrospective study.

OBJECTIVE

To evaluate the clinical and functional outcomes in patients with spinal cord injury (SCI) and preexisting ankylosing spondylitis (AS).

SUMMARY OF BACKGROUND DATA

AS alters the strength and biomechanical properties of the spine that renders it susceptible to fracture with minimal trauma. Neurologic involvement is common and outcomes largely depend on the early recognition and appropriate management.

METHODS

A 10-year review (1996-2005) was carried out to identify all patients admitted with SCI associated with AS. The cause of injury, prehospital and emergency management, definitive treatment of fracture, final neurology, and functional outcomes were ascertained. Reasons for neurologic deterioration were determined.

RESULTS

Eighteen patients were identified. In 15 patients, the injury resulted from trauma (fall 14, road accident 1) and in 3 the SCI followed spinal surgical interventions. Twelve of the 15 patients with traumatic injuries were able to walk immediately after the fall but subsequently deteriorated for various reasons. Spinal epidural hematomas developed in 3 patients (2 traumatic, 1 spinal intervention). The fractures were managed surgically in 3 patients, halo jacket was used in 2, and the remainder were managed expectantly on traction. Four patients died before discharge, 4 were able to walk with an aid at discharge, and the others were wheel chair dependent.

CONCLUSION

Neurologic deficits were often subtle on initial presentation, resulting in many injuries being missed because of a low index of suspicion and poor visualization of lower cervical fractures on conventional radiographs. Extension of the ankylosed kyphotic cervical spine during conventional immobilization or for radiologic procedures resulted in neurologic deficits. Patients with an ankylosed cervical spine are normally unable to see the ceiling lying supine because of cervicothoracic kyphosis and use pillows to support their head. Cervical spine alignment in a similar flexed position is essential during immobilization or imaging. Medical alert cards as for patients with diabetes would be a way forward in correctly identifying patients with AS so that appropriate precautions can be instituted by emergency services.

Dynamic postural balance in ankylosing spondylitis patients

OBJECTIVES

In this study, our objectives were to investigate whether patients with ankylosing spondylitis (AS) have a poorer dynamic balance than normal subjects, and to study the relationship between balance and posture.

METHODS

Seventy patients (57 men, 13 women) with AS and 35 (31 men, 4 women) controls matched for age, weight, height and body mass index were tested using the Biodex Stability System. Anteroposterior (AP), mediolateral (ML) and overall (OA) indices were obtained with bilateral stance at platform stabilities of 8 and 4. Subjects were tested with 'eyes open' at all times. Correlation analyses were performed between stability indices (OA, AP, ML) and disease duration, cervical rotation (CR), tragus to wall distance (TWD), lumbar side flexion (LSF), lumbar flexion (LF), intermalleolar distance (IMD) and Bath Ankylosing Spondylitis Metrology Index (BASMI) total score.

RESULTS

No significant difference was found between the AS patients and healthy subjects with respect to all three stability indices at levels 4 and 8. A positive correlation was found only between ML stability index and TWD at level 8 (r, 0.249; P = 0.038). No other positive correlation was detected between stability indices and CR, TWD, LSF, LF, IMD, total BASMI score and disease duration.

CONCLUSIONS

AS has no negative effect on postural stability. The only clinically significant association was found between dynamic postural balance and TWD.