Time course and correlates of psychological distress post spinal surgery: A longitudinal study.

Background: Psychological distress post lumbar spine surgery is associated with poorer outcomes. There is a scarcity of studies devoted to analyzing the risk factors associated with psychological distress in patients who have undergone lumbar fusion surgery. The purpose of this study was to (1) describe the time course and severity of psychological distress using the STarT Back Tool (SBT) and (2) determine the demographic and clinical predictors of SBT score post lumbar spine fusion surgery. Methods: This retrospective longitudinal study analyzed 227 subjects with 1- and 2-level lumbar fusion surgery who underwent standardized assessment preoperatively and at 4 and 12 weeks postoperatively. Preoperative variables collected were demographic, clinical, and psychological variables. Postoperative psychological distress was measured by self-reported SBT. Risk factors for SBT over time were identified using ordinal and mixed-effects modelling. Results: Although the trajectory of SBT levels declined postoperatively over time, at week-12, 20% of patients had moderate to high SBT. Postoperative SBT scores at week-4 time point was significantly greater than SBT scores at week-8 (OR = 2.7, 95% credible interval [CrI]; 1.8-3.9). Greater SBT scores at week-4 were strongly associated with greater SBT scores throughout 12 weeks of follow-up (OR = 7.3, [95% CrI; 1.2-31.4]). Greater postoperative SBT levels over time were associated with being male (OR = 2.2, 95% CrI; 1.0-3.9), greater preoperative back or leg pain intensity (OR = 2.2; 95% CrI: 1.0-4.4), greater preoperative leg weakness (OR = 4.2, 95% CrI: 1.7-7.5) and higher preoperative depression levels (OR = 4.8; 95% CrI: 1.6-10.4). Conclusion: Postoperative SBT levels declined nonlinearly over time. However, a sizable proportion of patients had moderate to high psychological distress at week-12 postsurgery. Greater preoperative back or leg pain intensity, leg weakness and depression levels, and male gender were risk factors of greater psychological distress postsurgery. Although requiring validation, our study has identified potential modifiable risk factors which may give an opportunity to provide early (preoperative) and targeted strategies to optimize postoperative psychosocial outcomes in patients undergoing lumbar fusion surgeries.

Factors Associated with Pain Intensity and Walking Disability After Lumbar Fusion: A Longitudinal Study.

STUDY DESIGN: Retrospective longitudinal study. OBJECTIVE: To identify the preoperative factors associated with postoperative lumbar fusion recovery in back or leg pain, self-reported walking time, and gait speed over a 6-month period. SUMMARY OF BACKGROUND DATA: The demand for lumbar fusion surgeries has significantly increased over the years. Yet, some patients report persistent postsurgical pain and poor functional outcomes. Unfortunately, the associated risk factors are not well understood. METHODS: The study analyzed 232 subjects with mono- or bisegmental lumbar fusion surgery who underwent standardized assessment preoperatively and at 4, 12, and 24weeks postoperatively. Preoperative variables collected were demographic, clinical, and psychological variables. Back or leg pain was measured by the Numeric Pain Rating Scale. Walking disability was measured by self-reported walking time and performance-based fast gait speed. Risk factors of pain and walking disability over time were identified using ordinal and linear mixed-effects modeling. RESULTS: At 6 months post-surgery, 17% of patients reported having moderate or severe back/leg pain and 24% were unable to walk longer than 30 minutes. Greater preoperative self-reported leg weakness frequency and body-mass-index (BMI) were strongly associated with greater pain and walking disability. Additionally, greater preoperative depression symptoms were associated with greater back/leg pain (adjusted odds ratio = 4.0) and shorter walking time (adjusted odds ratio = 2.7)-but not with slower gait speed (difference = 0.01 m/s). Old age and female gender were strongly associated with gait speed but not with self-reported walking time. CONCLUSION: A sizable proportion of patients had poor pain and walking outcomes even at 6 months post-surgery. Preoperative leg weakness and BMI were consistent risk factors and patients with greater depression symptoms may have poorer self-reported outcomes. Although requiring validation, our study has identified potentially modifiable risk factors which may give clinicians an opportunity to provide early (preoperative) and targeted intervention strategies to optimize postoperative outcomes.Level of Evidence: NA.

An exploratory study examining factors underpinning postural instability in older adults with idiopathic neck pain.

There is limited understanding of potential mechanisms underpinning postural control deficits in people with neck pain. This study examined several characteristics that might explain impaired postural stability in a group of older adults with neck pain, and compared the results in this cohort with that of asymptomatic controls. In this cross-sectional study we compared physical activity, lower limb motor and sensory function, vestibular and visual function, falls efficacy and dizziness handicap in 84 older adults with (n=35, age 69.6±6.3) and without (n=49, age 69.4±4.7) idiopathic neck-pain. Additionally, dynamic balance was assessed using the dynamic gait index (DGI) and standard and wavelet analysis of static balance was computed after data capture. Physical activity levels, lower limb motor and sensory function, vestibular function and visual contrast sensitivity were not different between groups (p>0.05). The neck-pain group demonstrated higher falls efficacy (p=0.01), greater levels of dizziness handicap (p<0.01), and higher CoP velocity measures in the moderate (1.56-6.25Hz) and low (0.39-1.56Hz) frequency bandwidths. Our results suggest that neck-pain induced postural control deficits in older adults may not be associated with the physical activity levels, lower limb motor and sensory function, or vestibular and visual function. Inferring from wavelet analysis results, we speculated that sensory re-weighting may have occurred to compensate for the deficits in neck proprioception. Further research is warranted to determine neck specific mechanisms underpinning postural control dysfunction in neck pain.

The concurrent validity and intrarater reliability of the Microsoft Kinect to measure thoracic kyphosis.

This study aims to investigate the concurrent validity and intrarater reliability of the Microsoft Kinect to measure thoracic kyphosis against the Flexicurve. Thirty-three healthy individuals (age: 31±11.0 years, men: 17, height: 170.2±8.2 cm, weight: 64.2±12.0 kg) participated, with 29 re-examined for intrarater reliability 1-7 days later. Thoracic kyphosis was measured using the Flexicurve and the Microsoft Kinect consecutively in both standing and sitting positions. Both the kyphosis index and angle were calculated. The Microsoft Kinect showed excellent concurrent validity (intraclass correlation coefficient=0.76-0.82) and reliability (intraclass correlation coefficient=0.81-0.98) for measuring thoracic kyphosis (angle and index) in both standing and sitting postures. This study is the first to show that the Microsoft Kinect has excellent validity and intrarater reliability to measure thoracic kyphosis, which is promising for its use in the clinical setting.

Intra-rater reliability of hallux flexor strength measures using the Nintendo Wii Balance Board.

BACKGROUND: The purpose of this study was to investigate the intra-rater reliability of a new method in combination with the Nintendo Wii Balance Board (NWBB) to measure the strength of hallux flexor muscle. METHODS: Thirty healthy individuals (age: 34.9 ± 12.9 years, height: 170.4 ± 10.5 cm, weight: 69.3 ± 15.3 kg, female = 15) participated. Repeated testing was completed within 7 days. Participants performed strength testing in sitting using a wooden platform in combination with the NWBB. This new method was set up to selectively recruit an intrinsic muscle of the foot, specifically the flexor hallucis brevis muscle. Statistical analysis was performed using intra-class coefficients and ordinary least product analysis. To estimate measurement error, standard error of measurement (SEM), minimal detectable change (MDC) and percentage error were calculated. RESULTS: Results indicate excellent intra-rater reliability (ICC = 0.982, CI = 0.96-0.99) with an absence of systematic bias. SEM, MDC and percentage error value were 0.5, 1.4 and 12 % respectively. CONCLUSIONS: This study demonstrates that a new method in combination with the NWBB application is reliable to measure hallux flexor strength and has potential to be used for future research and clinical application.

Validity and intra-rater reliability of an android phone application to measure cervical range-of-motion.

BACKGROUND: Concurrent validity and intra-rater reliability using a customized Android phone application to measure cervical-spine range-of-motion (ROM) has not been previously validated against a gold-standard three-dimensional motion analysis (3DMA) system. FINDINGS: Twenty-one healthy individuals (age:31 ± 9.1 years, male:11) participated, with 16 re-examined for intra-rater reliability 1-7 days later. An Android phone was fixed on a helmet, which was then securely fastened on the participant's head. Cervical-spine ROM in flexion, extension, lateral flexion and rotation were performed in sitting with concurrent measurements obtained from both a 3DMA system and the phone.The phone demonstrated moderate to excellent (ICC = 0.53-0.98, Spearman ρ = 0.52-0.98) concurrent validity for ROM measurements in cervical flexion, extension, lateral-flexion and rotation. However, cervical rotation demonstrated both proportional and fixed bias. Excellent intra-rater reliability was demonstrated for cervical flexion, extension and lateral flexion (ICC = 0.82-0.90), but poor for right- and left-rotation (ICC = 0.05-0.33) using the phone. Possible reasons for the outcome are that flexion, extension and lateral-flexion measurements are detected by gravity-dependent accelerometers while rotation measurements are detected by the magnetometer which can be adversely affected by surrounding magnetic fields. CONCLUSION: The results of this study demonstrate that the tested Android phone application is valid and reliable to measure ROM of the cervical-spine in flexion, extension and lateral-flexion but not in rotation likely due to magnetic interference. The clinical implication of this study is that therapists should be mindful of the plane of measurement when using the Android phone to measure ROM of the cervical-spine.

New insights into neck-pain-related postural control using measures of signal frequency and complexity in older adults.

There is evidence to implicate the role of the cervical spine in influencing postural control, however the underlying mechanisms are unknown. The aim of this study was to explore standing postural control mechanisms in older adults with neck pain (NP) using measures of signal frequency (wavelet analysis) and complexity (entropy). This cross-sectional study compared balance performance of twenty older adults with (age=70.3±4.0 years) and without (age=71.4±5.1 years) NP when standing on a force platform with eyes open and closed. Anterior-posterior centre-of-pressure data were processed using wavelet analysis and sample entropy. Performance-based balance was assessed using the Timed Up-and-Go (TUG) and Dynamic Gait Index (DGI). The NP group demonstrated poorer functional performance (TUG and DGI, p<0.01) than the healthy controls. Wavelet analysis revealed that standing postural sway in the NP group was positively skewed towards the lower frequency movement (very-low [0.10-0.39Hz] frequency content, p<0.01) and negatively skewed towards moderate frequency movement (moderate [1.56-6.25Hz] frequency content, p=0.012). Sample entropy showed no significant differences between groups (p>0.05). Our results demonstrate that older adults with NP have poorer balance than controls. Furthermore, wavelet analysis may reveal unique insights into postural control mechanisms. Given that centre-of-pressure signal movements in the very-low and moderate frequencies are postulated to be associated with vestibular and muscular proprioceptive input respectively, we speculated that, because NP demonstrate a diminished ability to recruit the muscular proprioceptive system compared to controls, they rely more on the vestibular system for postural stability.

Neck musculature fatigue affects specific frequency bands of postural dynamics during quiet standing.

Proprioceptive input from the neck is important for maintenance of upright standing. Although neck musculature fatigue has been demonstrated to impair standing balance, there is limited understanding of the underlying postural mechanisms. This study aimed to further examine the effects of neck musculature fatigue on standing by using modern analysis of center of pressure (CoP) data. Forty-eight young healthy adults stood quietly on a balance board for 1 min before and after performing repeated weight-resisted scapular elevation exercises. In a supplementary study on 20 participants, we examined (i) the effects of visual deprivation and (ii) the test-retest reliability of the traditional and wavelet-based CoP measures. Test-retest reliability of the CoP measures was moderate to good (intraclass correlation coefficients ranged from 0.58 to 0.94). With neck muscle fatigue or without vision, traditional measures of CoP velocity and standard deviation increased monotonically. Wavelet analysis revealed that CoP velocity within the ultralow (<0.10 Hz) and moderate (1.56-6.25 Hz) frequency bands increased post-fatigue. Without vision, CoP velocity increased in all but the ultralow frequency band. Our data suggest that post-fatigue, vision may be the main compensatory postural mechanism for altered neck proprioception. In conclusion, our findings reveal more nuances than the simple assertion that neck musculature fatigue increased postural sway and they advocate the use of wavelet analysis in examining postural mechanisms associated with neck proprioception.

The influence of cervical spine flexion-rotation range-of-motion asymmetry on postural stability in older adults.

STUDY DESIGN: Cross-sectional design. OBJECTIVE: The purpose of this study was to isolate the contribution of cervical spine range-of-motion (ROM) asymmetry to postural control in a group of older adults with neck pain. SUMMARY OF BACKGROUND DATA: Previous research has suggested that the upper cervical spine plays an important role in postural stability. However, it remains unclear whether the upper cervical spine rotation ROM asymmetry is associated with postural stability. METHODS: Using the cervical range-of-motion device to assess upper cervical spine ROM via the cervical flexion-rotation test, we classified 54 older adults with neck pain (30 females; mean [standard deviation] age, 66 [5] yr) into the (1) symmetrical group (SYM; n = 20; ≤5° side-to-side difference) or (2) asymmetrical group (ASYM; n = 34; >5° difference). Standing postural control was characterized by the center-of-pressure (CoP) movements measured using a Balance Board. Other measures included habitual, fast-paced gait speed and neck pain. Both groups were compared on the various measures using Welch t tests. RESULTS: Although the ASYM group had 26% greater anteroposterior postural sway than the SYM (P < 0.01), both groups did not differ on postural sway velocity, gait speed, and neck pain intensity. Analyzing the frequency content of the postural sway using wavelet analysis (a modern, nonlinear signal processing method) shed further light: the standing postural sway in the ASYM group was skewed toward lower frequency movement (ultralow [< 0.10Hz] frequency content, anteroposterior: 6.7% in ASYM, 4.7% in SYM, P = 0.01; medial-lateral: 4.2% in ASYM, 3.4% in SYM, P = 0.045). CONCLUSION: The ASYM group seemed to have compensated for their altered somatosensory input to achieve similar functional levels as the SYM group. Given what is known about the association between ultralow frequency postural sway and visual input, we speculated that the postural strategy adopted by the ASYM group was adaptive and that this group may be relying on the visual system to achieve these compensations.

Effects of thoracic kyphosis and forward head posture on cervical range of motion in older adults.

It is unclear how age-related postural changes such as thoracic spine kyphosis influence cervical range-of-motion (ROM) in patients with cervical spine dysfunction. The purpose of this study was to explore the mediating effects of forward head posture (FHP) on the relationship between thoracic kyphosis and cervical mobility in older adults with cervical spine dysfunction. Fifty-one older adults (30 females, mean[SD]age = 66[4.9] years) with cervical spine dysfunction - that is, cervical pain with or without referred pain, numbness or paraesthesia - participated. Pain-related disability was measured using the neck disability index (NDI). Thoracic kyphosis was measured using a flexicurve. FHP was assessed via the craniovertebral angle (CVA) measured from a digitized, lateral-view photograph of each subject. Cervical ROM - namely, upper and general cervical rotation and cervical flexion - was measured by the Cervical Range-of-Motion (CROM) device. Greater thoracic kyphosis was significantly associated with lesser CVA (Spearman ρ = -0.48) whereas greater CVA was significantly associated with greater cervical flexion (Spearman ρ = 0.30) and general rotation ROM (ρ = 0.33), but not with upper cervical rotation ROM (ρ = 0.15). Bootstrap mediational analyses, adjusted for age, gender, weight and NDI, revealed significant indirect effects of thoracic kyphosis on cervical flexion and general rotation ROM through a FHP. Our results show that FHP mediated the relationship between thoracic kyphosis and cervical ROM, specifically general cervical rotation and flexion. These results not only support the justifiable attention given to addressing FHP to improve cervical impairments, but they also suggest that addressing thoracic kyphosis impairments may constitute an "upstream" approach.