Abdominal Compartment Syndrome Secondary to Bulimia Nervosa: A Case Report and Systematic Review of Published Cases.

BACKGROUND: Abdominal compartment syndrome (ACS) is typically attributed to critically unwell patients with trauma, burns, post surgery, and massive ascites. A rare but fatal cause of ACS is bulimia nervosa (BN), which is an eating disorder characterized by bingeing, followed by methods to avoid weight gain, including purging. CASE REPORT: We present a case of a 20-year-old woman who presented with abdominal pain and distension after consuming a large quantity of food the previous night and was unable to purge. She was initially managed conservatively and discharged home, but returned subsequently on the same day with clinical features of ACS secondary to acute gastric distension. Decompression resulted in life-threatening reperfusion injury with critical electrolyte abnormalities and fatal cardiac arrest in the operating theatre. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: A systematic review of the literature found only 11 case reports of ACS secondary to BN, of which only 6 patients survived due to early diagnosis and decompression. Inability to purge and lower limb ischemia appeared to be associated with increased mortality. As BN is a common emergency presentation, the case and systematic review highlights the need to consider ACS as a potentially life-threatening complication of binge eating, particularly when there is unsuccessful purging.

Ultrasound-guided supraclavicular block versus Bier block for emergency reduction of upper limb injuries: a protocol for an open-label, non-inferiority, randomised controlled trial.

BACKGROUND: Closed reduction of upper limb fractures and/or dislocations are common in the emergency department (ED), which involves physically re-aligning the injured part prior to immobilisation. As this is painful, numerous techniques are available to provide regional anaesthesia to ensure patient tolerance. A Bier block (BB) is typically performed as part of routine care. An alternative technique gaining interest in the ED is ultrasound-guided supraclavicular block (UGSCB), which involves injecting local anaesthetic around the brachial plexus at the supraclavicular fossa under ultrasound guidance. It is unclear whether UGSCB is effective and safe when performed in the ED. METHODS: SUPERB (SUPraclavicular block for Emergency Reduction versus Bier block) is a prospective open-label, non-inferiority randomised controlled trial that compares the effectiveness of UGSCB versus BB for closed reduction of upper limb fractures and/or dislocations. Adult patients presenting with an upper limb fracture and/or dislocation that requires emergent closed reduction in the ED will be eligible. After screening, participants will be randomised to either UGSCB or BB. Once regional anaesthesia is obtained, closed reduction of the injured part will be performed and appropriately immobilised. The primary outcome is maximal pain experienced during closed reduction measured via a visual analogue scale (VAS). Secondary outcomes include baseline and post-reduction pain, patient satisfaction, total opioid requirement in ED, ED length of stay, adverse events and regional anaesthesia failure. DISCUSSION: Existing evidence suggests UGSCB is effective when performed in the operating theatre by trained anaesthetists. SUPERB will be the first randomised controlled trial to elucidate the effectiveness and safety of UGSCB in the ED. The findings have the potential to provide an alternative safe and effective option for the management of upper extremity emergencies in the ED. TRIAL REGISTRATION: This trial has been registered on 21 October 2022 with Australia and New Zealand Clinical Trials Registry (ACTRN12622001356752).

Prolonged length of stay is associated with reduced hand hygiene compliance in the emergency department: A single centre retrospective study.

OBJECTIVE: To examine whether patient flow factors in the ED such as prolonged length of stay are associated with hand hygiene (HH) compliance. METHODS: We conducted a retrospective study at an urban district hospital utilising available data from January 2018 to December 2021. Compliance to the World Health Organization five moments of HH expressed as percentage of total moments observed were collated every 2 months. Patient flow measures including proportion of patients referred or discharged within 4 h (LOS4), proportion of patients with ED length of stay >24 h (LOS24) and total number of patient presentations, were obtained for each 2-month periods. The association between these patient flow measures and HH compliance was examined using Pearson's correlation (P < 0.05). RESULTS: The results showed a moderate and significant association between rates of HH compliance and LOS24 (r = -0.48, P = 0.025). That is, lower proportion of patients with ED length of stay >24 h was associated with improved HH compliance. There was no significant correlation between HH compliance and LOS4 (r = 0.38, P = 0.085) or total number of ED presentations (r = -0.30, P = 0.17). CONCLUSIONS: The findings show that prolonged ED length of stay may explain, at least partly, lower rates of HH compliance. Improvements in ED HH compliance should also include strategies that enhance patient flow.

Impact of electric scooters to a tertiary emergency department: 8-week review after implementation of a scooter share scheme.

OBJECTIVE: A retrospective audit of presentations to a tertiary trauma centre reviewing the demographics of electric scooter injuries in the first 2 months of the scooter-share scheme, which was commenced in Brisbane in November 2018. METHODS: Electric scooter-associated presentations to the Royal Brisbane and Women's Hospital Emergency and Trauma Centre from November 2018 to January 2019 were identified. Data collected included patient demographics, type and location of injuries, helmet use, alcohol consumption, length of stay and disposition. Estimates of costs associated with electric scooter presentation were also obtained. RESULTS: Fifty-four electric scooter encounters were included during the 2-month period. Helmets were worn in 46% and was associated with reduced risk of head injury (odds ratio (OR) 0.18, P = 0.029). Alcohol was involved in 27% although this did not impact on admission rates (OR 1.25, P = 0.83) or operative management (OR 2.14, P = 0.42). Contusions/abrasions and fractures/dislocations were the most common types of injury, whereas upper limb and minor head injuries were the most common sites of injury. Most patients were discharged home (87%), with 74% completing their emergency visit in under 4 h. Six patients required operative management and 15 patients needed outpatient follow-up. There were no deaths. Average patient cost per presentation was $542 and ranged from $285 to $1345. CONCLUSIONS: The findings characterised injury patterns and costs associated with electric scooters in our ED. Given the increasing popularity of electric scooters as an alternate form of transportation, our study may help to inform public policy for future injury prevention.

Shoulder Taping and Neuromuscular Control.

CONTEXT: Scapular taping can offer clinical benefit to some patients with shoulder pain; however, the underlying mechanisms are unclear. Understanding these mechanisms may guide the development of treatment strategies for managing neuromusculoskeletal shoulder conditions. OBJECTIVE: To examine the mechanisms underpinning the benefits of scapular taping. DESIGN: Descriptive laboratory study. SETTING: University laboratory. PATIENTS OR OTHER PARTICIPANTS: A total of 15 individuals (8 men, 7 women; age = 31.0 ± 12.4 years, height = 170.9 ± 7.6 cm, mass = 73.8 ± 14.4 kg) with no history of shoulder pain. INTERVENTION(S): Scapular taping. MAIN OUTCOME MEASURE(S): Surface electromyography (EMG) was used to assess the (1) magnitude and onset of contraction of the upper trapezius (UT), lower trapezius (LT), and serratus anterior relative to the contraction of the middle deltoid during active shoulder flexion and abduction and (2) corticomotor excitability (amplitude of motor-evoked potentials from transcranial magnetic stimulation) of these muscles at rest and during isometric abduction. Active shoulder-flexion and shoulder-abduction range of motion were also evaluated. All outcomes were measured before taping, immediately after taping, 24 hours after taping with the original tape on, and 24 hours after taping with the tape removed. RESULTS: Onset of contractions occurred earlier immediately after taping than before taping during abduction for the UT (34.18 ± 118.91 milliseconds and 93.95 ± 106.33 milliseconds, respectively, after middle deltoid contraction; P = .02) and during flexion for the LT (110.02 ± 109.83 milliseconds and 5.94 ± 92.35 milliseconds, respectively, before middle deltoid contraction; P = .06). These changes were not maintained 24 hours after taping. Mean motor-evoked potential onset of the middle deltoid was earlier at 24 hours after taping (tape on = 7.20 ± 4.33 milliseconds) than before taping (8.71 ± 5.24 milliseconds, P = .008). We observed no differences in peak root mean square EMG activity or corticomotor excitability of the scapular muscles among any time frames. CONCLUSIONS: Scapular taping was associated with the earlier onset of UT and LT contractions during shoulder abduction and flexion, respectively. Altered corticomotor excitability did not underpin earlier EMG onsets of activity after taping in this sample. Our findings suggested that the optimal time to engage in rehabilitative exercises to facilitate onset of trapezius contractions during shoulder movements may be immediately after tape application.

Measuring Pain for Patients Seeking Physical Therapy: Can Functional Magnetic Resonance Imaging (fMRI) Help?

In the multidisciplinary fields of pain medicine and rehabilitation, advancing techniques such as functional magnetic resonance imaging (fMRI) are used to enhance our understanding of the pain experience. Given that such measures, in some circles, are expected to help us understand the brain in pain, future research in pain measurement is undeniably rich with possibility. However, pain remains intensely personal and represents a multifaceted experience, unique to each individual; no single measure in isolation, fMRI included, can prove or quantify its magnitude beyond the patient self-report. Physical therapists should be aware of cutting-edge advances in measuring the patient's pain experience, and they should work closely with professionals in other disciplines (eg, magnetic resonance physicists, biomedical engineers, radiologists, psychologists) to guide the exploration and development of multimodal pain measurement and management on a patient-by-patient basis. The primary purpose of this perspective article is to provide a brief overview of fMRI and inform physical therapist clinicians of the pros and cons when utilized as a measure of the patient's perception of pain. A secondary purpose is to describe current known factors that influence the quality of fMRI data and its analyses, as well as the potential for future clinical applications relevant to physical therapist practice. Lastly, the interested reader is introduced and referred to existing guidelines and recommendations for reporting fMRI research.

Gain of postural responses increases in response to real and anticipated pain.

This study tested two contrasting theories of adaptation of postural control to pain. One proposes alteration to the postural strategy including inhibition of muscles that produce painful movement; another proposes amplification of the postural adjustment to recruit strategies normally reserved for higher load. This study that aimed to determine which of these alternatives best explains pain-related adaptation of the hip muscle activity associated with stepping down from steps of increasing height adaptation of postural control to increasing load was evaluated from hip muscle electromyography (fine-wire and surface electrodes) as ten males stepped from steps of increasing height (i.e. increasing load). In one set of trials, participants stepped from a low step (5 cm) and pain was induced by noxious electrical stimulation over the sacrum triggered from foot contact with a force plate or was anticipated. Changes in EMG amplitude and onset timing were compared between conditions. Hip muscle activation was earlier and larger when stepping from higher steps. Although ground reaction forces (one of the determinants of joint load) were unchanged before, during and after pain, trials with real or anticipated noxious stimulation were accompanied by muscle activity indistinguishable from that normally reserved for higher steps (EMG amplitude increased from 9 to 17 % of peak). These data support the notion that muscle activation for postural control is augmented when challenged by real/anticipated noxious stimulation. Muscle activation was earlier and greater than that required for the task and is likely to create unnecessary joint loading. This could have long-term consequences if maintained.

Changes in the integrity of thalamocortical connections are associated with sensorimotor deficits in children with congenital hemiplegia.

Preservation of thalamocortical projections to the sensorimotor cortex is related to improved hand function in children with cerebral palsy (CP). Whether CP is associated with altered microstructure of these sensorimotor projections or other thalamocortical pathways remains unclear. Forty-two children with congenital hemiplegia and fifteen typically developing children (TDC) underwent structural and diffusion-weighted imaging (high-angular-resolution diffusion imaging) using a 3T MRI. Structural T1-images were parcellated into 34 cortical regions and the thalamus per hemisphere. Thalamocortical projections were extracted using probabilistic tractography and the top tan cortical regions with the greatest number of thalamocortical streamlines for the TDC group were selected for further analysis. The thalamus was parcellated based on its cortical connections. Differences between hemispheres for thalamocortical streamline numbers to each cortical region [asymmetry index (AI)], tract volume and tract microstructure [weighted mean fractional anisotropy (FA) and mean diffusivity (MD)] were calculated. Correlations between these measures (AI, FA and MD) and sensorimotor function were performed. Thalamocortical projections showed topographical organisation based on cortical connectivity. Projections to paracentral lobule, pre-central and post-central gyri showed greater AI in CP group, which indicates reduced streamlines on the ipsilesioned hemisphere. Reduced FA, reduced tract volume and increased MD were also found for these thalamocortical projections on the ipsilesioned hemisphere in children with CP. Changes in AI and tract microstructure of these projections were associated with poorer sensorimotor function. The findings suggest CP is associated with reorganisation of thalamocortical projections to the sensorimotor cortex. Integrity in these projections may underpin deficits in sensorimotor function.

Recognising neuroplasticity in musculoskeletal rehabilitation: a basis for greater collaboration between musculoskeletal and neurological physiotherapists.

Evidence is emerging for central nervous system (CNS) changes in the presence of musculoskeletal dysfunction and pain. Motor control exercises, and potentially manual therapy, can induce changes in the CNS, yet the focus in musculoskeletal physiotherapy practice is conventionally on movement impairments with less consideration of intervention-induced neuroplastic changes. Studies in healthy individuals and those with neurological dysfunction provide examples of strategies that may also be used to enhance neuroplasticity during the rehabilitation of individuals with musculoskeletal dysfunction, improving the effectiveness of interventions. In this paper, the evidence for neuroplastic changes in patients with musculoskeletal conditions is discussed. The authors compare and contrast neurological and musculoskeletal physiotherapy clinical paradigms in the context of the motor learning principles of experience-dependent plasticity: part and whole practice, repetition, task-specificity and feedback that induces an external focus of attention in the learner. It is proposed that increased collaboration between neurological and musculoskeletal physiotherapists and researchers will facilitate new discoveries on the neurophysiological mechanisms underpinning sensorimotor changes in patients with musculoskeletal dysfunction. This may lead to greater integration of strategies to enhance neuroplasticity in patients treated in musculoskeletal physiotherapy practice.

Reduced integrity of sensorimotor projections traversing the posterior limb of the internal capsule in children with congenital hemiparesis.

There is reduced integrity of corticospinal projections that traverse the posterior limb of the internal capsule (PLIC) in children with unilateral cerebral palsy (CP). It remains unclear whether there are changes in integrity of other projections traversing the PLIC. Forty children with congenital hemiparesis and 15 typically developing children underwent structural and diffusion-weighted MRI. All children with congenital hemiparesis showed lesions to the periventricular white matter. Structural images were parcellated into 34 cortical regions per hemisphere and posterior limb of the internal capsule was identified. PLIC connections to each cortical region were extracted using probabilistic tractography. Differences between hemispheres for each cortical projection (asymmetry index (AI)) and tract microstructure (fractional anisotropy (FA), mean diffusivity (MD)) were assessed. The results showed that 17 children (42.5%) with congenital hemiparesis showed bilateral lesions on structural MRI. Projections to the primary motor cortex (precentral gyrus and paracentral lobule) showed greater asymmetry in unilateral CP group compared to typically developing children and indicate reduced projections on the hemisphere contralateral to the impaired limb (i.e., contralateral hemisphere). Reduced FA and increased MD were also observed for connections with the primary motor cortex, primary sensory cortex (postcentral gyrus) and precuneus on the contralateral hemisphere in children with congenital hemiparesis. Similar changes were observed between children with unilateral and bilateral lesions on structural MRI. Notably, microstructural changes were associated with deficits in both sensory and motor function. The findings further unravel the underlying neuroanatomical correlates of sensorimotor deficits in children with congenital hemiparesis.

Recruitment of discrete regions of the psoas major and quadratus lumborum muscles is changed in specific sitting postures in individuals with recurrent low back pain.

STUDY DESIGN: Cross-sectional controlled laboratory study. OBJECTIVES: To investigate potential changes in the function of discrete regions of the psoas major (PM) and quadratus lumborum (QL) with changes in spinal curvatures and hip positions in sitting, in people with recurrent low back pain (LBP). BACKGROUND: Although the PM and QL contribute to control of spinal curvature in sitting, whether activity of these muscles is changed in individuals with LBP is unknown. METHODS: Ten volunteers with recurrent LBP (pain free at the time of testing) and 9 pain-free individuals in a comparison group participated. Participants with LBP were grouped into those with high and low erector spinae (ES) electromyographic (EMG) signal amplitude, recorded when sitting with a lumbar lordosis. Data were recorded as participants assumed 3 sitting postures. Fine-wire electrodes were inserted with ultrasound guidance into fascicles of the PM arising from the transverse process and vertebral body, and the anterior and posterior layers of the QL. RESULTS: When data from those with recurrent LBP were analyzed as 1 group, PM and QL EMG signal amplitudes did not differ between groups in any of the sitting postures. However, when subgrouped, those with low ES EMG had greater EMG signal amplitude of the PM vertebral body and QL posterior layer in flat posture and greater EMG signal amplitude of the QL posterior layer in short lordotic posture, compared to those in the pain-free group. For the group with high ES EMG, the PM transverse process and PM vertebral body EMG was less than that of the other LBP group in short lordotic posture. CONCLUSION: The findings suggest a redistribution of activity between muscles that have a potential extensor moment in individuals with LBP. The modification of EMG of discrete fascicles of the PM and QL was related to changes in ES EMG signal amplitude recorded in sitting.

Changes in direction-specific activity of psoas major and quadratus lumborum in people with recurring back pain differ between muscle regions and patient groups.

Psoas major (PM) and quadratus lumborum (QL) muscles have anatomically discrete regions. Redistribution of activity between these regions has been observed in people with low back pain (LBP). We hypothesised that the bias of activity of specific regions of PM and QL towards trunk extension may change depending on whether LBP individuals have more or less erector spinae (ES) activity in an extended/upright lumbar posture. Ten volunteers with recurring episodes of LBP and nine pain-free controls performed isometric trunk efforts in upright sitting. LBP individuals were subgrouped into those with high and low ES electromyographic activity (EMG) when sitting with a lumbar lordosis. Fine-wire electrodes were inserted into fascicles of PM arising from the transverse process (PM-t) and vertebral body (PM-v) and anterior (QL-a) and posterior layers (QL-p) of QL. The LBP group with low ES EMG had greater bias of PM-t, PM-v and QL-p towards trunk extension. The LBP group with high ES activity showed less PM activity towards extension. These findings suggest redistribution of activity within and/or between these muscles with extensor moments. This is likely to be important to consider for effective clinical interventions for individuals with LBP.

Changes in regional activity of the psoas major and quadratus lumborum with voluntary trunk and hip tasks and different spinal curvatures in sitting.

STUDY DESIGN: Cross-sectional controlled laboratory study. OBJECTIVES: To investigate the function of discrete regions of psoas major (PM) and quadratus lumborum (QL) with changes in spinal curvature and hip position. BACKGROUND: Anatomically discrete regions of PM and QL may have differential function on the lumbar spine, based on anatomical and biomechanical differences in their moment arms between fascicles within each muscle. METHODS: Fine-wire electrodes were inserted with ultrasound guidance into PM fascicles arising from the transverse process (PM-t) and vertebral body (PM-v) and anterior (QL-a) and posterior (QL-p) layers of QL. Recordings were made on 9 healthy participants, who performed 7 tasks with maximal voluntary efforts and adopted 3 sitting postures that involved different spinal curvatures and hip angles. RESULTS: Activity of PM-t was greater during trunk extension than flexion, whereas activity of PM-v was greater during hip flexion than trunk efforts. Activity of QL-p was greater during trunk extension and lateral flexion, whereas QL-a showed greater activity during lateral flexion. During sitting tasks, PM-t was more active when sitting with a short lordosis than a flat (less extended) lumbar spine posture, whereas PM-v was similarly active in both sitting postures. CONCLUSION: Activity of PM-t was more affected by changes in position of the lumbar spine than the hip, whereas PM-v was more actively involved in the movement of the hip rather than that of the lumbar spine. Moreover, from its anatomy, PM-t has a combined potential to extend/lordose the lumbar spine and flex the hip, at least in a flexed-hip position.

Altered trunk muscle coordination during rapid trunk flexion in people in remission of recurrent low back pain.

People with a history of low back pain (LBP) are at high risk to encounter additional LBP episodes. During LBP remission, altered trunk muscle control has been suggested to negatively impact spinal health. As sudden LBP onset is commonly reported during trunk flexion, the aim of the current study is to investigate whether dynamic trunk muscle recruitment is altered in LBP remission. Eleven people in remission of recurrent LBP and 14 pain free controls performed cued trunk flexion during a loaded and unloaded condition. Electromyographic activity was recorded from paraspinal (lumbar and thoracic erector spinae, latissimus dorsi, deep and superficial multifidus) and abdominal muscles (obliquus internus, externus and rectus abdominis) with surface and fine-wire electrodes. LBP participants exhibited higher levels of co-contraction of flexor/extensor muscles, lower agonistic abdominal and higher antagonistic paraspinal muscle activity than controls, both when data were analyzed in grouped and individual muscle behavior. A sub-analysis in people with unilateral LBP (n = 6) pointed to opposing changes in deep and superficial multifidus in relation to the pain side. These results suggest that dynamic trunk muscle control is modified during LBP remission, and might possibly increase spinal load and result in earlier muscle fatigue due to intensified muscle usage. These negative consequences for spinal health could possibly contribute to recurrence of LBP.

Deficits in reaction time due to increased motor time of peroneus longus in people with chronic ankle instability.

The purpose of this study was to investigate whether neuromuscular adaptations at the site of injury or neural adaptation remote to the injury are affected in individuals with chronic ankle instability (CAI). Electromyography data were collected from the peroneus longus (PL) and tibialis anterior during an ankle joint reaction time task in 12 participants with unilateral CAI and 12 healthy control participants. Following an auditory cue, time to onset of muscle activity (pre-motor time) and time from onset of muscle activity to movement (motor time) were measured during rapid ankle eversion and dorsiflexion. Reaction time for ankle eversion on the affected side was significantly slower in the CAI group than the control group, due to significantly slower motor time for the PL. Changes in motor time for the affected PL in participants with CAI may be attributed to a combination of factors associated with local tissue changes.

Differential activity of regions of the psoas major and quadratus lumborum during submaximal isometric trunk efforts.

Controversy exists regarding the function of psoas major (PM) and quadratus lumborum (QL) at the lumbar spine. The functions of discrete regions of PM and QL were studied during trunk loading tasks. Twelve healthy participants performed isometric trunk loading tasks in various directions in upright sitting. Fine-wire electromyography (EMG) electrodes were inserted under ultrasound guidance into PM fascicles arising from the transverse process (PM-t) and vertebral body (PM-v) and the anterior (QL-a) and posterior (QL-p) layers of QL on the right side. Although right PM-t and PM-v were both active during right lateral-flexion trunk efforts, their activity was opposite in the sagittal plane, with greater PM-t towards extension and PM-v towards flexion. QL-a and QL-p were similarly active, though QL-p was active to a greater percentage of MVC during right trunk lateral-flexion efforts. Activity of QL-p was modulated with respiratory phase during the loading tasks with trunk efforts towards the right lateral-flexion/flexion and right lateral-flexion directions. These findings provide novel understanding of the unique activation of discrete regions of PM and QL. These differences must be considered in future EMG studies to better understand the function of these deeply situated trunk muscles in the control of the lumbar spine.

The effect of pain on training-induced plasticity of the corticomotor system.

UNLABELLED: Pain is thought to interfere with training-induced plasticity of corticomotor pathways. Although this implies direct interference with plastic processes, it may be explained by compromised performance in the training task during pain. Repeated finger movements can induce plasticity and change the amplitude/direction of acceleration of finger movement evoked by transcranial magnetic stimulation (TMS). We hypothesized that if pain interferes with plasticity, acceleration of finger movement would not change when the training task was painful, despite control of training task performance. TMS was applied over the optimal scalp site to evoked index finger abduction movements in nine participants. Participants then trained finger adduction with feedback of finger acceleration for three 8-min sessions, in three conditions on separate days. CONDITIONS: first dorsal interosseus (FDI) pain and control (no-pain), with injection of 5% and 0.9% hypertonic saline, respectively, into FDI; and remote pain (5% saline injection into infrapatellar fat pad). Peak acceleration of TMS-evoked finger movement and amplitude of motor evoked potentials (MEPs) in FDI were measured at baseline, between training sessions, and at three 5-min intervals after training ceased. Plastic change was observed (reduced TMS evoked peak finger acceleration in the abduction direction) after motor training during control and FDI pain, but not during the remote pain. There was no change in FDI MEPs in any conditions. These data do not support direct effects of nociceptive input (pain) on training-induced plasticity of corticomotor pathways. Remote pain may compromise learning due to distraction from the training task or other complex central pain processes.

ISSLS prize winner: Smudging the motor brain in young adults with recurrent low back pain.

STUDY DESIGN: Cross-sectional design. OBJECTIVE: To investigate whether recurrent low back pain (LBP) is associated with changes in motor cortical representation of different paraspinal muscle fascicles. SUMMARY OF BACKGROUND DATA: Fascicles of the lumbar paraspinal muscles are differentially activated during function. Human studies indicate this may be associated with a spatially separate array of neuronal networks at the motor cortex. Loss of discrete control of paraspinal muscle fascicles in LBP may be because of changes in cortical organization. METHODS: Data were collected from 9 individuals with recurrent unilateral LBP and compared with 11 healthy participants from an earlier study. Fine-wire electrodes selectively recorded myoelectric activity from short/deep fascicles of deep multifidus (DM) and long/superficial fascicles of longissimus erector spinae (LES), bilaterally. Motor cortical organization was investigated using transcranial magnetic stimulation at different scalp sites to evoke responses in paraspinal muscles. Location of cortical representation (center of gravity; CoG) and motor excitability (map volume) were compared between healthy and LBP groups. RESULTS: Individuals with LBP had a more posterior location of LES center of gravity, which overlapped with that for DM on both hemispheres. In healthy individuals, LES center of gravity was located separately at a more anterior location to that for DM. Map volume was reduced in LBP compared to healthy individual across muscles. CONCLUSION: The findings highlight that LBP is associated with a loss of discrete cortical organization of inputs to back muscles. Increased overlap in motor cortical representation of DM and LES may underpin loss of differential activation in this group. The results further unravel the neurophysiological mechanisms of motor changes in recurrent LBP and suggest motor rehabilitation that includes training of differential activation of the paraspinal muscles may be required to restore optimal control in LBP.