Purpose of study and background. Spinal muscle area (SMA) is often employed to assess muscle functionality and is important for understanding the risk individuals may have of developing back pain or the risk of postural instability and falls.. However, handgrip strength (HGS) has also been utilized as a measure of general muscle capacity. This study aimed to examine the relationship between SMA and HGS to assess whether the latter could be used as an accurate indicator of the former. Methods. 150 participants (75 males and 75 females, aged 47–70 years) were selected from the UK Biobank dataset. Handgrip strength values were extracted and averaged over left and right values. Abdominal MRI images were examined and cross-sectional area of the erector spinae and multifidus determined at the L3/4 level and summed to provide a total muscle area. Results. HGS and SMA (mean±sd) were 39.6 ± 7.4 kg and 4664 ± 868 mm. 2. for males and 24.7 ± 5.9 kg, and 3822 ± 579 mm. 2. for females. Pearson correlation between HGS and SMA was r = 0.41 for males (p = <0.001), r = 0.40 for females (p = <0.001), and r = 0.61 for the combined groups (p<0.001). Conclusion. Significant correlations were found between HGS and SMA for individual sexes and combined groups. However, although HGS may be a useful measure for predicting modifications in group responses in spinal muscle function, for example, following an intervention, it does not have the power to confidently predict muscle values at an individual participant level. Conflicts of interest: No conflicts of interest. Sources of funding: Prince Sattam University, KSA, provided a PhD scholarship for Salman Alharthi

Background. Trunk muscles play an important role in supporting the spinal column. A decline in trunk muscle mass, as measured by bioelectrical impedance analysis (TMM–BIA), is associated with low back pain and poor quality of life. Purpose. The purpose of this study was to determine whether TMM–BIA correlates with quantitative and functional assessments traditionally used for the trunk muscles. Methods. We included 380 participants (aged ≥ 65 years; 152 males, 228 females) from the Shiraniwa Elderly Cohort (Shiraniwa) study, for whom the following data were available: TMM–BIA, lumbar magnetic resonance imaging (MRI), and back muscle strength (BMS). We measured the cross-sectional area (CSA) and fat-free CSA of the paravertebral muscles (PVM), including the erector spinae (ES), multifidus (MF), and psoas major (PM), on an axial lumbar MRI at L3/4. The correlation between TMM–BIA and the CSA of PVM, fat-free CSA of PVM, and BMS was investigated. Results. TMMBIA correlated with the CSA of total PVM and each individual PVM. A stronger correlation between TMM–BIA and fat-free CSA of PVM was observed. The TMM–BIA also strongly correlated with BMS. Conclusion. TMM–BIA is an easy and reliable way to evaluate the trunk muscle mass in a clinical setting. Conflict of interest. None. Sources of funding. None

Although interlaminar endoscopic lumbar discectomy (IELD) is considered to be less invasive than microscopic lumbar discectomy (MLD) in treatment of lumbar herniated nucleus pulposus, the radiologic change of multifidus muscles by each surgery has rarely been reported. The aim of the present study was to compare the quantitative and qualitative changes of multifidus muscles between two surgical approaches and to analyze the correlation between various parameters of multifidus muscles and long term surgical outcome. 21 patients who received MLD and 18 patients who received IELD in a single tertiary hospital were enrolled and their preoperative, postoperative (≤15 days), and follow-up (≥6 months) MRIs were analyzed. The cross-sectional area (CSA) and fatty degeneration rate (FD) were quantitatively estimated at the level of surgery. The correlations among CSA, FD, body mass index, follow-up visual analogue scale(VAS) and Oswestry Disability Index(ODI) were assessed. Mean intervals of postoperative MRI and follow-up MRI from surgery were 3.0±3.7 days and 14.5±10.7 months, respectively. During the follow-up period, VAS was improved from 7.1±1.3 to 2.1±1.8 in MLD and from 8.2±1.4 to 2.2±1.8 in IELD. In cases of MLD, comparing with preoperative MRI, ipsilateral CSA was significantly increased in postoperative MRI (795.6mm. 2. vs. 906.5mm. 2. , p<0.01), but it was not significantly different in follow-up MRI (795.6mm. 2. vs. 814.4mm. 2. , p=1.00). However, in case of IELD, the ipsilateral CSAs in preoperative, postoperative, and follow-up periods were 892.0 mm. 2. , 909.3 mm. 2. , and 900.3 mm. 2. , respectively. These changes were not significant over time (p=0.691). The ipsilateral FDs were not significantly changed between preoperative and follow-up periods in both MLD (21.4% vs. 20.9%, p=0.81) and IELD groups (23.5% vs. 21.8%, p=0.19). The increment of ipsilateral CSA had significant correlations with follow-up ODI (r=−0.368, p=0.02). Comparing with IELD, MLD induced more surgical trauma on multifidus muscle in postoperative period, but the muscular damage was recovered in follow-up period. IELD can minimize surgical trauma on multifidus muscle showing similar pain relief as MLD. Favorable surgical outcome in follow-up period may be related to increment of multifidus muscle volume. Figure 1. (A-C) The multifidus muscles in preoperative, postoperative, and follow-up periods, respectively, in patient with MLD. Comparing with preoperative period, the CSA of right multifidus muscle (ipsilateral side) was increased in postoperative period, but recovered in follow-up period. (D-F) The multifidus muscle in preoperative, postoperative, and follow-up periods, respectively, in patient with IELD. The CSA of left multifidus muscles (ipsilateral side) was not significantly changed over time. Comparing preoperative MRIs with follow-up MRIs, the FDs of multifidus muscles were not significantly changed regardless of surgical technique. Figure 2. The CSA was measured by marking region of interest (ROI) and FD was measured by calculating the rate of pixels beyond the threshold in ROI. All measurements were performed using ImageJ software (version 1.52a, National Institutes of Health, Bethesda, Maryland, USA). For any figures or tables, please contact the authors directly

Purpose of the study. To assess the ability of magnetic resonance spectroscopy (MRS) to detect changes in spinal muscle metabolism after a 4-week exercise intervention. Background. Spinal muscle atrophy is associated with back pain and exercise interventions have been shown to reduce pain and improve function. It is not always clear, however, whether improvements are due to enhanced muscle performance or occur for other reasons (e.g. psychological, neurological). MRS can be used to measure muscle metabolism and could therefore be useful for assessing the mechanisms by which exercise improves function in back pain patients. Methods. Eleven healthy participants took part in a 4-week exercise intervention to strengthen the spinal muscles. Before and after the intervention, the participants underwent an assessment that included using MRS to monitor the phosphocreatine levels in the spinal muscles around the level of L3L4 whilst they performed a modified Biering-Sorensen test to fatigue. Results. Relative to the pre-intervention assessment, the post-intervention endurance time significantly increased (mean=20 s, 95% CI 7–34 s, p=0.01). The phosphocreatine depletion, taken at an equivalent time point in both assessments, significantly decreased (mean=12%, 95% CI 5–19%, p=0.006). Even at the point of the fatigue, the phosphocreatine depletion was lower post-intervention (mean=8%, 95%CI 1–15%, p=0.045). Conclusion. MRS can be used to detect changes in the metabolism of the spinal muscles after a 4-week exercise intervention

Background. Previous work has identified differential kinematics and muscle activity between non-specific chronic low back pain (LBP) subgroups (flexion pattern (FP) and active extension pattern) and healthy controls. However, it is unclear if differences in muscle activity are maintained on resolution of pain and/or if they contribute to pain recurrence. Purpose. To investigate differences in trunk muscle activity between individuals with a history of flexion-related LBP (who are currently pain-free) and no-LBP controls during three functional activities. Methods. Fifteen individuals (10 male, 5 female) with a previous history of FP LBP (but who were currently pain-free) and 15 individuals with no history of low back pain (10 male, 5 female) were recruited. Surface electromyography of bilateral superficial lumbar multifidus, longissimus thoracis, transversus abdominus/internal oblique and external oblique muscle activity was recorded during three functional activities (sit-to-stand, step-up and bending to pick up a pen from the floor). Surface electromyography data was normalised (% maximum voluntary contraction) and compared between groups (Mann-Whitney U test). Results. No significant differences were observed for any muscle in any activity (p>0.05) except for significantly increased right superficial lumbar multifidus during the bending task (p=0.04) in the FP group compared to the control group (36.55 vs. 19.97 respectively). Conclusion. Individuals with resolved FP LBP have similar trunk muscle activation to those with no history of LBP. This suggests that muscle activity behaviours may ‘normalise’ in FP on resolution of pain. Further work should explore muscle activity during recurrent episodes to establish links with pain provocation. No conflicts of interest. No funding obtained

Purpose & Background. The ability to jump higher is a key factor for athletic performance and relies on many factors including spinal movement and trunk muscle activity. Manual therapy including Mulligan' Sustained Natural Apophyseal Glide (SNAG) techniques are proposed to increase spinal movement and thus function. The evidence pf the effect of manual therapy on muscle activity is limited. We aimed to determine the immediate effects of an extension SNAG on the lower lumbar spine on jump height and rectus abdominis (RA), external oblique (EO), multifidus (M) and iliocostalis Lumborum (IL) muscle activity during the flight phase of vertical jump compared to a placebo intervention (flat hand pressure). Method. Eighteen healthy participants (16 males, age 28.11±5.01 years, weight 70.58±11.9 kg, height 1.70±0.07m, body mass index 24.28±3.30)from Cardiff University were randomly allocated to either an extension SNAG or placebo intervention. Surface Electromyography was normalised to maximum voluntary contraction and was collected during the flight phase of the jump and jump height was measured using jump and reach test. Results. There was a significant increase (p=0.01) in jump height for the SNAG group. No significant differences in RA, EO, M, IL muscle activity was noted between SNAG and placebo interventions In EO, LES and M descriptive analysis showed a decrease in muscle activity in on average 14 of the subjects. Conclusion. SNAG mobilisation can produce an immediate increase in jump height but no significant changes in muscle activity in healthy subjects. Further work is warranted in subjects with low back pain. No Conflict of Interests. No funding was obtained

To compare the complication profile of a muscle splitting approach to the anterior cervical spine with previously described approaches. The authors describe and compare the complications of an approach that exposes the anterior cervical spine by directly splitting the strap muscles in the midline with blunt dissection thereby potentially reducing iatrogenic complications. A retrospective review of 62 operations to the anterior cervical spine, between 2002 and 2009. Indications: Fusion and arthroplasty procedures for brachalgia, axial neck pain and trauma. The postoperative complications. The complication rate was favourable compared to previously described approaches. The muscle splitting approach to the anterior cervical spine has a low complication rate compared to previously described approaches, and allows the cervical spine to be approached with blunt dissection thereby potentially minimising iatrogenic approach related complications

Background and Aim. Spinal stability is associated with low back pain and affects the spines ability to support loads. Stability can be achieved if the applied force follows the curvature of the spine, passing close to the vertebral centroids. Previously we showed that calculated muscle forces required for stability in an idealised model increased with increasing and more evenly distributed lumbar curvatures. The purpose of this study was to calculate the muscle forces required for stability in standing in a group of healthy adults. Methods. Positional MRI was used to acquire sagittal images of the lumbar spine in a standing posture in 30 healthy adults. Sacral inclination was measured and active shape modelling used to characterise lumbar spine shape. A two-dimensional model of the lumbar spine was constructed using vertebral centroid positions and a simplified representation of the lumbar extensor muscles. The muscle forces required at each level to produce a follower load were calculated using a force polygon. Results. Sacral angle was positively correlated with the amount of overall curvature in the lumbar spine (P<0.001) but not the distribution of curvature. Muscle forces increased with increasing curvature at all lumbar levels (P<0.02). The distribution of curvature affected the muscle forces only at L3 (P<0.03). Conclusion. In a sample of healthy adults, muscle forces required to maintain stability are determined by the overall curviness of the lumbar spine and, to a lesser extent, the distribution of curvature. Variations in spinal shape should be considered when modelling lumbar spine loading. This abstract has not been previously published in whole or substantial part nor has it been presented previously at a national meeting. Conflicts of interest: No conflicts of interest. Sources of funding: This work was supported by a studentship granted to the University and awarded to AVP. An NHS Endowment grant provided further funding

Background. Trunk muscle activity and thoraco-lumbar kinematics have been shown to discriminate non-specific chronic low back pain (NSCLBP) subgroups from healthy controls. Thoracic spine kinematics and muscle activity whilst intuitively associated with NSCLBP, has received less attention and the possibility of intra-regional interactions remains an area for exploration. Purpose. Determine relationships between muscle activation and kinematics in active extension pattern (AEP) and flexion pattern (FP) subgroups and no-low back pain controls during a sagittal bending task. Methods. Fifty NSCLBP subjects (27 FP, 23 AEP) and 28 healthy controls underwent 3D motion analysis (Vicon™) and surface electromyography whilst bending to retrieve a pen from the floor. Mean sagittal angle for the upper and lower thoracic and lumbar regions (UTx, LTx, ULx, LLx) were compared with normalised mean amplitude electromyography of 4 bilateral trunk muscles. Pearson correlations were computed to assess relationships. Results. Significant relationships between lumbar multifidus and ULx/LLx were identified in AEP during bending and return (p<0.01). FP exhibited multiple significant interactions including between longissimus thoracis and lumbar multifidus and LLx/LTx (p<0.035); and external oblique activity and UTx/LTx (p<0.05) during bending and return (and LLx during bending). Correlations were moderate to strong (r= −0.812 to 0.664). Conclusion. Kinematic and trunk muscle activity measurements differentiated between NSCLBP sub-groups and controls, especially between LLx kinematics and lumbar multifidus activity. Contrasting muscle activation patterns between LLx and LTx regions in FP highlights the importance of regional thoracic measurements, and suggests likely compensation strategies. Replication during other tasks should be evaluated in future studies. No conflicts of interest. Funding provided by Versus Arthritis (Formerly Arthritis Research UK)

Purpose. To determine the effect of leg dominance on trunk muscle activity during bridging exercises on the floor and a gym ball. Background. Perturbation training including bridging exercises and unstable surfaces have been shown to increase trunk activity. Trunk muscle activity increases on the contralateral side to the stabilising leg during bridging, however, no studies exist on the effect of leg dominance on trunk muscle activity during bridging exercises. This study will investigate whether trunk muscle activity differs when stabilising on the dominant versus non-dominant leg. Method. A same subject observational design collected surface electromyography (SEMG) muscle activity for right (R) and left (L) bilateral IO and EO in 2 bridging exercises. (1) feet on the floor, (2) legs on a gym ball. 13 subjects, all right leg dominant (age, 21.53±1.50 years, height 169.38±8.33 centimetres, weight 67.91±10.60 kilograms gave informed consent. All SEMG data was normalized against maximum voluntary contractions. Data was analysed using paired t-test or Wilcoxon rank analysis. Results. In the ball exercise lifting the dominant leg significantly increased RIO (p=0.004), in the floor exercise lifting the dominant leg significantly increased LEO (p=0.03) and RIO (p=0.05). In the ball exercise lifting the non-dominant leg significantly increased LIO p=(0.007) and LEO (p=0016). All other recordings were non-significant. Conclusion. There was no consistency in increase in trunk muscle activity when comparing lifting the dominant and non dominant leg in the two exercise conditions. This may reflect the variability in individual trunk muscle response to perturbations

Introduction. The usefulness of markers of non-specific low back pain (NSLBP), including MRI derived measurements of cross-sectional area (CSA) and functional CSA (FCSA, fat free muscle area) of the lumbar musculature, is in doubt. To our knowledge, such markers remain unexplored in Lumbar Disc Degeneration (LDD), which is significantly associated with NSLBP, Modic change and symptom recurrence. This exploratory 3.0-T MRI study addresses this shortfall by comparing asymmetry and composition in asymptomatic older adults with and without Modic change. Methods. A sample of 21 healthy, asymptomatic subjects participated (mean age 56.9 years). T2-weighted axial lumbar images were obtained (L3/L4 to L5/S1), with slices oriented through the centre of each disc. Scans were examined by a Consultant MRI specialist and divided into 2 groups dependent on Modic presence (M) or absence (NM). Bilateral measurements of the CSA and FCSA of the erector spinae, multifidus, psoas major and quadratus lumborum were made using Image-J software. Muscle composition was determined using the equation [(FCSA/CSA)*100] and asymmetry using the equation [(Largest FCSA-smallest FCSA)/largest FCSA*100]. Data were analysed using Mann-Whitney U tests (p value set at). Intrarater reliability was examined using Intraclass Correlations (ICCs). Results. ICCs ranged between 0.74 and 0.96 for all area measurements, indicating excellent reliability. There was no significant difference in TCSA and FCSA asymmetry (P=0.1–1.0) and muscle composition (P=0.1–1.0) between M and NM groups. Conclusion. Modic change in the absence of pain does not appear to influence cross-sectional asymmetry or composition of the lumbar musculature. CSA remains a controversial marker. No conflicts of interest. Funding: This work is funded by an Allied Health Professional Doctoral Fellowship awarded to Janet Deane by Arthritis Research U.K

Introduction. Chronic low back pain (LBP) is globally recognised as a leading cause of disability, with a global point-prevalence of 540 million people experiencing ‘activity-limiting’ LBP. A lack of muscle endurance is common in people with LBP, however the mechanisms underlying reduced endurance remain unclear. This study utilised high-density EMG (HDEMG) to evaluate differences in the spatial distribution and redistribution of lumbar erector spinae (ES) activity during an endurance task. Methods. Thirteen control (Age:26.46±5.0, 7 Males) and 13 LBP participants (Age:27.39±9.7, 6 Males) were recruited and HDEMG signals were detected from ES unilaterally using a 13×5 electrode grid adhered 2cm lateral to the L5 spinous process. Participants were asked to complete an isometric endurance task until failure (>10° trunk deviation) with muscle activity simultaneously recorded. The activity was computed to form a map of the EMG amplitude distribution and the position of the centre of activity (centroid) was monitored throughout the task. Results. The LBP group showed significantly lower endurance than controls (LBP:186.2±72.3s, control:283.0±33.0s). The EMG map showed a less diffuse contraction of ES in LBP participants, with greater activation in cranial portions. In the LBP group, throughout the task the centroid was 12mm more cranial, and less redistribution of activity was seen (LBP:1.40±0.29mm, control:2.10±0.45mm). Conclusions. LBP participants utilised a different motor strategy to complete the task, characterised by more cranial activation of ES and less redistribution of activity. These findings provide new insight into the mechanisms underlying impaired endurance in people with LBP and may lead to the development of new exercise approaches. Conflicts of interest: No conflicts of interest. Sources of funding: No funding obtained

Statement of Purpose. It is well known that individuals with a history of low back pain (hLBP) exhibit altered movement patterns that are caused by changes in neuromuscular control. Postural disturbance provides an effective method for creating these differentiable movement patterns. This study has explored the response of the lower limb and spine to a translational perturbation similar to that experienced on public transport in healthy volunteers and those with hLBP. Methods. Healthy volunteers (n=16) and subjects with hLBP (n=10) were subjected to 31 identical postural disturbances at varying time intervals while standing atop a moving platform. Skeletal kinematics and muscle activation were recorded using a 10-camera Vicon system (Oxford, UK) and Myon electromyography (EMG) at the trunk (lumbar, lower thoracic, and upper thoracic segments), pelvis, thigh, calf, and foot. Joint angles were calculated using Body Builder (Vicon) and a unilateral seven-segment custom model. Results. Examination of the total range of joint motion (RoM) exhibited during the trial demonstrated similar RoM at the knee and hip (p=0.90 and 0.97 respectively), but less RoM for the hLBP group at the ankle and lumbar spine (p=0.21 and 0.38, respectively). EMG signals revealed higher muscle activation of the lower limbs from the hLBP cohort compared to healthy controls, yet greater activation at the gluteal and oblique muscles in the control group. Conclusions. In the presently small cohorts, trends demonstrate that differences in postural strategies exist between the healthy and hLBP cohorts, yet further testing of LBP patients will further clarify targets for rehabilitation

Staying active, including walking is promoted as being beneficial for patients with low back pain (LBP). The abdominal muscles appear to influence the stability of the spine and their activity has been shown to change when patients have LBP. Walking with Nordic walking poles has been shown to influence forces on the lower limbs, but little research has investigated the effect on the trunk muscles. Aim: to study the effect of walking using Nordic walking poles on abdominal muscle activity and lower limb forces. Method 15 healthy subjects gave informed consent (5 males. 10 females, age 21.06 yrs.(±88), height 174.45cms (±11.1), weight 71.44 kg (±15.2)). Following a period of walking training with Nordic walking poles data was obtained during a period of walking for internal IO) and external oblique (EO) using surface electromyography activity and vertical lower limb forces (Newtons, (N)) with (WP) and without Nordic walking poles (NP). SEMG data was normalised to maximum voluntary contraction. Results. There were significant increases in IO (p=0.02, NP 31.94 (±39.9) WP 53.05 (±40.61)), EO (p=0.02, NP 46.45, (±30.9), WP 87.93 ± (±60.5)) and vertical forces with poles (p=0.008, NP871.6 (±237.00)N, WP 968.33, (±210.8) N). Discussion. Using Nordic walking poles significantly increases activity of IO and EO, which may be of value in the rehabilitation of some patients with LBP. Vertical forces increased when walking with poles which is contrary to previous research. This may be due to the data collection setting of a research laboratory or the subjects being novice walkers

We recorded compound muscle action potentials (CMAPs) from the diaphragm in 15 normal volunteers, nine patients with lesions of the lower cervical cord (C5 to C8), one completely quadriplegic patient (C6) and seven patients with lesions at a higher cervical level (C1 to C4). Transcranial magnetic stimulation and electrical stimulation of the phrenic nerve were carried out. When the centre of the coil was placed on the interauricular line at a point 3 cm lateral to the vertex on the scalp, the CMAPs from the diaphragm had the largest amplitude and the shortest latency. There was no difference in the mean latency of the CMAPs recorded by transcranial magnetic stimulation in the normal volunteers and in the patients with lesions of the lower cervical cord. In the quadriplegic patient, the latency of the CMAPs was not delayed, but was prolonged in the patients with lesions at a higher level. Those evoked by electrical stimulation of the phrenic nerve were not prolonged in the patients with higher lesions. Our findings suggest that the prolongation of the latency by transcranial magnetic stimulation reflects dysfunction of the higher cervical cord. The combination of transcranial magnetic stimulation and electrical stimulation of the phrenic nerve can detect the precise level of the lesion in the motor tract to the diaphragm

Purpose. Cognitive Muscular Therapy (CMT) is a new treatment for low back pain which integrates psychological techniques for pain management alongside training to improve postural control. Rather than focus on postural alignment or strength, CMT aims to improve the regulation of postural tone (low-level activity which supports the body against gravity). This is achieved by teaching patients an awareness of compensatory paraspinal activation, which can be triggered by overactivity of the abdominal muscles. The aim of this study was to understand whether CMT could reduce symptoms associated with low back pain and improve paraspinal muscle activation. Methods and results. Fifteen patients with chronic low back pain received seven weekly sessions of CMT from a physiotherapist. Clinical data was captured at baseline and two weeks after the intervention using the Roland-Morris questionnaire and the pain catastrophising scale. Activation of the erector spinae muscle during walking was also measured at baseline and after the final intervention session. Change data were analysed using paired t-tests. There was a 75% reduction (p<0.001) in the Roland-Morris score from a mean (SD) of 9.3(2.9) to 2.3(2.6), along with a 78% reduction in pain catastrophising (p<0.002) from 16.6(13) to 3.7(4.8). Activation of the contralateral erector spinae muscles reduced by 30% (p<0.01) during the contralateral swing phase of walking. Conclusion. In this small sample, CMT delivered large clinical improvements and reduced activation of the low back muscles during walking. Larger randomised trials are now required to confirm whether CMT could outperform existing physiotherapy treatments for chronic back pain. Conflict of interest. No conflicts of interest. Source of funding. University of Salford

Purpose and Background. Clinical practice guidelines (CPGs) recommend self-management for low back pain (LBP). Our recent narrative review on self-management needs revealed a consensus with respect to the critical components of self-management interventions. With mobile health advancements, apps offer innovative support for LBP management. This study aims to identify current apps for the self-management of LBP, assessing them for their quality, intervention content, theoretical approaches, and risk management approaches. Methods and Results. We identified 69 apps for LBP self-management from a systematic search in the UK iTunes and Google Play stores. The most recommended interventions are muscle stretching (n=51, 73.9%), muscle strengthening (n=42, 60.9%), and core stability exercises (n=32, 46.4%). The average MARS (SD) overall score for the included apps was 2.4 (0.44) out of a possible 5 points, with the engagement and information dimension scoring the lowest at 2.1. In terms of theoretical and risk management approaches, no apps offered a theoretical care model and all failed to specify the age group targeted; only one (1.4%) provided a tailored care approach; 18 (26.1%) included intervention progression; and 11 (15.9%) reported management safety checks. Conclusion. This study shows that app developers generally select interventions endorsed by CPGs. However, the application of a biopsychosocial care model is not being considered. Most of them are of low quality, lacking theoretical approaches to care and consideration of associated risks. It is essential to involve clinicians and patients in developing LBP self-management apps to improve the quality and related approach. Conflicts of interest. None. Sources of funding. No funding obtained. This study has been published in JMIR mHealth and uHealth

Aims. Adult spinal deformity (ASD) surgery can reduce pain and disability. However, the actual surgical efficacy of ASD in doing so is far from desirable, with frequent complications and limited improvement in quality of life. The accurate prediction of surgical outcome is crucial to the process of clinical decision-making. Consequently, the aim of this study was to develop and validate a model for predicting an ideal surgical outcome (ISO) two years after ASD surgery. Methods. We conducted a retrospective analysis of 458 consecutive patients who had undergone spinal fusion surgery for ASD between January 2016 and June 2022. The outcome of interest was achievement of the ISO, defined as an improvement in patient-reported outcomes exceeding the minimal clinically important difference, with no postoperative complications. Three machine-learning (ML) algorithms – LASSO, RFE, and Boruta – were used to identify key variables from the collected data. The dataset was randomly split into training (60%) and test (40%) sets. Five different ML models were trained, including logistic regression, random forest, XGBoost, LightGBM, and multilayer perceptron. The primary model evaluation metric was area under the receiver operating characteristic curve (AUROC). Results. The analysis included 208 patients (mean age 64.62 years (SD 8.21); 48 male (23.1%), 160 female (76.9%)). Overall, 42.8% of patients (89/208) achieved the ideal surgical outcome. Eight features were identified as key variables affecting prognosis: depression, osteoporosis, frailty, failure of pelvic compensation, relative functional cross-sectional area of the paraspinal muscles, postoperative sacral slope, pelvic tilt match, and sagittal age-adjusted score match. The best prediction model was LightGBM, achieving the following performance metrics: AUROC 0.888 (95% CI 0.810 to 0.966); accuracy 0.843; sensitivity 0.829; specificity 0.854; positive predictive value 0.806; and negative predictive value 0.872. Conclusion. In this prognostic study, we developed a machine-learning model that accurately predicted outcome after surgery for ASD. The model is built on routinely modifiable indicators, thereby facilitating its integration into clinical practice to promote optimized decision-making. Cite this article: Bone Joint J 2025;107-B(3):337–345

Spinal deformations are posture dependent. Official data from the Netherlands show that youth are encountering increasing problems with the musculoskeletal system (>40% back pain, and sport injury proneness). Prolonged sloth and slumped sitting postures are causative factors. Dutch youth are “champion sitting” in Europe. The effects of sitting on the development of posture and function of locomotion (stiffness) during growth have only been reported clearly in classic textbooks (in German) of practical anatomy and orthopaedics. Research with relevant clinical examinations is being done to understand epidemiological data on the increasing posture-dependent problems. A cohort of adolescents (15–18 years) in secondary school was assessed for sagittal postural deviations while bending. 248 children completed a questionnaire, and tests were done on neuromuscular tightness. The femorotibial angle was used to measure hamstring tightness. Measurement of the dorsiflexion of the foot was used to assess the tightness of calf muscles and Achilles tendons. All adolescents were photographed laterally while performing the finger–floor test (used to test flexibility), assessed as a knockout test: “Can you reach the floor or not?” The spinal profiles while bending were classified as abnormal arcuate or angular kyphosis. Hamstring tightness was present in 62.1% of the cohort in both legs, and in 18.2% unilaterally. Achilles tendon tightness was present bilaterally in 59.3%, and unilaterally in 19.4%. Activities with presence of stiffness (finger–floor distance), in descending order, were football, running, no sports, field hockey, tennis, dance, and gymnastics. 93.5% of the soccer players had tight hamstrings in both legs compared with none of those performing gymnastics. The correlation of the finger–floor test with tight hamstrings was 73.2%. For sagittal bending deformities, the correlation between form and function deficits cannot be made yet. 80 of 248 spines were rated by the examiners as having deformed flexion. Since Andry (1741) and at the zenith of continental orthopaedics and anatomy around 1900, the prolonged flexed positions of a young spine were indicated as being the main cause of deformity by overload and shear loads on immature discs and cartilage, preventing normal development of the discs. Nachemson proved that the intradiscal pressure in sitting adults was extremely high, so it follows that children must also be at risk. Evidence suggests that youth, generally because of their sedentary and “screenful lifestyle”, will encounter serious problems in growth, manifesting as incongruent neuro-osseous growth (Roth), serious neuromuscular tightness (being prone to injury), and spinal deformations, leading to pain

Purpose of study and background. Psychological factors are considered to play a role in development and maintenance of chronic low back pain (CLBP). Stress or anxiety can change pain sensitivity; however, this has predominantly been studied in healthy individuals with limited work in individuals with musculoskeletal pain. The objective of this study was to quantify the effect of acute exposure to a psychosocial stressor on mechanical pain sensitivity in individuals with and without CLBP. Summary of methods and results. Six individuals with CLBP and 10 individuals without CLBP performed a 10-minute computer task under conditions of low and high psychosocial stress. Psychosocial stress was manipulated using mental maths and memory tasks combined with social evaluative threat. The effect of the stressor was evaluated using blood pressure, heart rate and the state anxiety component of the Spielberger State-Trait Anxiety Index. Mechanical pressure pain threshold (PPT) was recorded on the tibialis anterior muscle using a handheld digital pressure algometer. The stress manipulation increased self-reported anxiety (p<0.001), but not blood pressure or heart rate (p>0.06). Change in PPT from low to high stress was greater in the CLBP group (median ΔPPT = −0.5 kg/cm. 2. ) than in the control group (−0.15 kg/cm. 2. ; p=0.005). Conclusion. Individuals experienced an increase in pain sensitivity after acute exposure to a stressor designed to mimic low-level workplace stressors, and this increase was greater in individuals with CLBP than asymptomatic individuals. These results indicate that this experimental model can be used to study links between pain sensitivity and psychosocial stressors and increase our understanding of their potential role in CLBP. Conflicts of Interest: No conflicts of interest. Sources of funding: No funding obtained