Extraction of Lumbar Spine Motion Using a 3-IMU Wearable Cluster.

Spine movement is a daily activity that can indicate health status changes, including low back pain (LBP) problems. Repetitious and continuous movement on the spine and incorrect postures during daily functional activities may lead to the potential development and persistence of LBP problems. Therefore, monitoring of posture and movement is essential when designing LBP interventions. Typically, LBP diagnosis is facilitated by monitoring upper body posture and movement impairments, particularly during functional activities using body motion sensors. This study presents a fully wireless multi-sensor cluster system to monitor spine movements. The study suggests an attempt to develop a new method to monitor the lumbopelvic movements of interest selectively. In addition, the research employs a custom-designed robotic lumbar spine simulator to generate the ideal lumbopelvic posture and movements for reference sensor data. The mechanical motion templates provide an automated sensor pattern recognition mechanism for diagnosing the LBP.

Quantifying External Load and Injury Occurrence in Women's Collegiate Volleyball Players Across a Competitive Season.

ABSTRACT: Taylor, JB, Barnes, HC, Gombatto, SP, Greenwood, D, and Ford, KR. Quantifying external load and injury occurrence in women's collegiate volleyball players across a competitive season. J Strength Cond Res 36(3): 805-812, 2022-Volleyball demands repetitive jumping, with high loads linked to risk of injury. The purpose of this study was to examine jumping demands and injury patterns throughout a women's volleyball season. Sixteen Division-I female volleyball players wore an accelerometer to record jump count (JC) and jump height during every practice and match throughout the season. Physical health was documented using a weekly modified Oslo Sports Trauma Research Center Overuse Injury Questionnaire (OSLO) and time-loss injuries were recorded. Multivariate analyses of variance were used to compare measures across phases of the season, between types of session (practice vs. match), and between injured and noninjured players (α = 0.05). Results showed the greatest training demands in the preseason with larger jump counts than during the nonconference, conference schedule, and postseason schedules (p < 0.001). Performance increased throughout the season with greater jump heights in the nonconference and conference schedule than in the preseason (p = 0.01). There were no significant differences in JC between practices (65.5 ± 30.5) and matches (67.5 ± 46.4). An injury incidence of 5.49 injures per 1,000 athletic exposures was identified, with injuries accounting for 31 days lost, or 2.1% of total exposures. Injuries affected performance throughout the season, as noted by an average weekly OSLO score of 15.1 ± 13.9%. Injured players had significantly lower jump counts per exposure (p = 0.03) and a larger variation in training load than uninjured players (coefficient of variation: injured = 54%, uninjured = 41%; p = 0.006). These data help provide coaches and clinicians for training and rehabilitation program designs.

Differences in lumbar spine and lower extremity kinematics in people with and without low back pain during a step-up task: a cross-sectional study.

BACKGROUND: Low back pain (LBP) affects more than one third of the population at any given time, and chronic LBP is responsible for increased medical costs, functional limitations and decreased quality of life. A clear etiology is often difficult to identify, but aberrant posture and movement are considered contributing factors to chronic LBP that are addressed during physiotherapy intervention. Information about aberrant movement during functional activities in people with LBP can help inform more effective interventions. The purpose of this study was to determine if there are differences in lumbar spine and lower extremity kinematics in people with and without LBP during a step-up task. METHODS: A convenience sample of 37 participants included 19 with LBP and 18 without a history of LBP. All participants were between the ages of 18 and 65, and controls were matched to participants with LBP based on age, gender and BMI. A motion capture system was used to record spine and lower extremity kinematics during the step-up task. ANOVA tests were used to determine differences in three-dimensional kinematics between groups. RESULTS: Participants with LBP displayed less lower lumbar motion in the sagittal plane (P = 0.001), more knee motion in the coronal plane (P = 0.001), and more lower extremity motion in the axial plane (P = 0.002) than controls. CONCLUSIONS: People with LBP display less lower lumbar spine motion in the sagittal plane and more out-of-plane lower extremity motion. Clinically, the step-up task can be used to identify these aberrant movements to develop more focused functional interventions for patients with LBP. TRIAL REGISTRATION: Not applicable.

An Endplate-Based Joint Coordinate System for Measuring Kinematics in Normal and Abnormally-Shaped Lumbar Vertebrae.

Vertebral level-dependent, angular, and linear translations of the spine have been measured in 2D and 3D using several imaging methods to quantify postural changes due to loading conditions and tasks. Here, we propose and validate a semiautomated method for measuring lumbar intervertebral angles and translations from upright MRI images using an endplate-based, joint coordinate system (JCS). This method was validated using 3D printed structures, representing intervertebral discs (IVD) at predetermined angles and heights, which were positioned between adjacent cadaveric vertebrae as a gold standard. Excellent agreement between our measurements and the gold standard was found for intervertebral angles in all anatomical planes (ICC > .997) and intervertebral distance measurements (ICC > .949). The proposed endplate-based JCS was compared with the vertebral body-based JCS proposed by the International Society of Biomechanics (ISB) using the 3D printed structures placed between 3 adjacent vertebrae from a cadaver with scoliosis. The endplate-based method was found to have better agreement with angles in the sagittal plane (ICC = 0.985) compared with the vertebral body-based method (ICC = .280). Thus, this method is accurate for measuring 3D intervertebral angles in the healthy and diseased lumbar spine.

Physical Therapists' Acceptance of a Wearable, Fabric-Based Sensor System (Motion Tape) for Use in Clinical Practice: Qualitative Focus Group Study.

BACKGROUND: Low back pain (LBP) is a costly global health condition that affects individuals of all ages and genders. Physical therapy (PT) is a commonly used and effective intervention for the management of LBP and incorporates movement assessment and therapeutic exercise. A newly developed wearable, fabric-based sensor system, Motion Tape, uses novel sensing and data modeling to measure lumbar spine movements unobtrusively and thus offers potential benefits when used in conjunction with PT. However, physical therapists' acceptance of Motion Tape remains unexplored. OBJECTIVE: The primary aim of this research study was to evaluate physical therapists' acceptance of Motion Tape to be used for the management of LBP. The secondary aim was to explore physical therapists' recommendations for future device development. METHODS: Licensed physical therapists from the American Physical Therapy Association Academy of Leadership Technology Special Interest Group participated in this study. Overall, 2 focus groups (FGs; N=8) were conducted, in which participants were presented with Motion Tape samples and examples of app data output on a poster. Informed by the Technology Acceptance Model, we conducted semistructured FGs and explored the wearability, usefulness, and ease of use of and suggestions for improvements in Motion Tape for PT management of LBP. FG data were transcribed and analyzed using rapid qualitative analysis. RESULTS: Regarding wearability, participants perceived that Motion Tape would be able to adhere for several days, with some variability owing to external factors. Feedback was positive for the low-profile and universal fit, but discomfort owing to wires and potential friction with clothing was of concern. Other concerns included difficulty with self-application and potential skin sensitivity. Regarding usefulness, participants expressed that Motion Tape would enhance the efficiency and specificity of assessments and treatment. Regarding ease of use, participants stated that the app would be easy, but data management and challenges with interpretation were of concern. Physical therapists provided several recommendations for future design improvements including having a wireless system or removable wires, customizable sizes for the tape, and output including range of motion data and summary graphs and adding app features that consider patient input and context. CONCLUSIONS: Several themes related to Motion Tape's wearability, usefulness, and ease of use were identified. Overall, physical therapists expressed acceptance of Motion Tape's potential for assessing and monitoring low back posture and movement, both within and outside clinical settings. Participants expressed that Motion Tape would be a valuable tool for the personalized treatment of LBP but highlighted several future improvements needed for Motion Tape to be used in practice.

Identifying Clinical Phenotypes in People Who Are Hispanic/Latino With Chronic Low Back Pain: Use of Sensor-Based Measures of Posture and Movement, Pain, and Psychological Factors.

OBJECTIVE: The aim of this study was to identify clinical phenotypes using sensor-based measures of posture and movement, pain behavior, and psychological factors in Hispanic/Latino people with chronic low back pain (CLBP). METHODS: Baseline measures from an ongoing clinical trial were analyzed for 81 Hispanic/Latino people with CLBP. Low back posture and movement were measured using commercial sensors during in-person testing and 8 hours of ecological monitoring. Magnitude, frequency, and duration of lumbar movements, sitting and standing postures were measured. Movement-evoked pain was assessed during in-person movement testing. Psychological measures included the Pain Catastrophizing Scale and the Fear Avoidance Beliefs Questionnaire. Random forest analysis was conducted to generate 2 groups and identify important variables that distinguish groups. Group differences in demographics, pain, psychological, and posture and movement variables were examined using t-tests and chi-square analyses. RESULTS: Two subgroups of Hispanic/Latino people with CLBP were identified with minimal error (7.4% misclassification ["out-of-bag" error]). Ecological posture and movement measures best distinguished groups, although most movement-evoked pain and psychological measures did not. Group 1 had greater height and weight, lower movement frequency, more time in sitting, and less time in standing. Group 2 had a greater proportion of women than men, longer low back pain duration, higher movement frequency, more time in standing, and less time in sitting. CONCLUSION: Two distinct clinical phenotypes of Hispanic/Latino people with CLBP were identified. One group was distinguished by greater height and weight and more sedentary posture and movement behavior; the second group had more women, longer duration of low back pain, higher lumbar spine movement frequency, and longer duration of standing postures. IMPACT: Ecological measures of posture and movement are important for identifying 2 clinical phenotypes in Hispanic/Latino people with CLBP and may provide a basis for a more personalized plan of care. LAY SUMMARY: Wearable sensors were used to measure low back posture and movement in Hispanic/Latino people with chronic low back pain. These posture and movement measures helped to identify 2 different clinical subgroups that will give physical therapists more information to better personalize treatment for chronic low back pain in Hispanic/Latino patients.

Pain-Related Anxiety in Spanish-Speaking Mexican Americans Who Report Chronic Pain: Psychometric Evaluation of a New Spanish Adaptation of the 20-Item Pain Anxiety Symptom Scale (PASS-20).

The 20-item Pain Anxiety Symptom Scale (PASS-20) was adapted for Spanish-speaking Mexican Americans who report chronic pain (SSMACP). The instrument measures pain-related anxiety with fear, physiological, avoidance/escape, and cognitive anxiety as subtypes. In SSMACP, the Spanish PASS-20's psychometric properties were evaluated while exploring relationships between pain-related anxiety with other variables. Using convenience sampling, 188 SSMACP (women = 108, men = 77; mean age = 37.20 years, standard deviation = 9.87) were recruited across the United States. Confirmatory factor analyses examined the structural validity of the hierarchical factor structure. Hierarchical multiple regression examined incremental validity. Correlational analyses examined convergent validity. Cronbach's coefficient alphas and McDonald's omegas examined internal consistency. Pearson's r, t-tests, and analysis of variance tests examined relationships between demographic variables and PASS-20 scores. Confirmatory factor analyses supported the hierarchical factor structure (root mean square error of approximation = .061, standardized root mean residual = .038, comparative fit index = .940). Total and subscale PASS-20 scores had acceptable convergent validity and internal consistency (range = .75-.93). Hierarchical multiple regression found that total and subscale PASS-20 scores have adequate incremental validity, considering that they contributed uniquely to the prediction of generalized anxiety scores above and beyond other pain-related scores. Demographic variables were significantly related to total and subscale PASS-20 scores. Evidence supports the use of Spanish total and subscale PASS-20 scores in SSMACP. Exploratory evidence also informed on the possible consequences and predictors of their pain-related anxiety. The results also encourage pain research in specific populations from Latin America (eg, Mexican Americans). PERSPECTIVE: The Spanish PASS-20 has adequate psychometric properties in SSMACP. This instrument can help catalyze pain research in SSMACP by informing on their pain-related anxiety and by helping evaluate other pain-related instruments. Evidence also informed on pain-related anxiety in SSMACP.

Protocol for a Parallel Group Randomized Clinical Trial Comparing a Culturally Adapted Cognitive Behavioral Telerehabilitation Intervention to Usual Physical Therapy for Latino Patients With Chronic Spine Pain.

OBJECTIVE: Disparities exist in health care access, diagnosis, and treatment of chronic pain in Latino populations and other minority populations. Cognitive behavioral-based physical therapy (CBPT) interventions have been shown to be effective in predominantly non-Hispanic white populations with chronic spine pain. However, there is a need for culturally adapted CBPT interventions that focus on the conservative management of chronic spine pain. The primary purpose of the study described in this protocol is to test the efficacy of an adapted cognitive behavioral-based hybrid telerehabilitation intervention for Latino patients with chronic spine pain. METHODS: A single-blind, 2-arm parallel group, superiority randomized clinical trial is planned to compare an adapted CBPT intervention to Usual Care physical therapy. Goal Oriented Activity for Latinos with chronic Spine pain (GOALS/Metas) is an 8-week hybrid telerehabilitation intervention that integrates guideline-based physical therapy and pain management interventions using cognitive behavioral approaches and has been adapted for Latino patients with chronic spine pain. Usual Care physical therapy will be administered based on institutional standards at the referring health center. Outcome measures will be evaluated preintervention and at 1-week, 3-months, and 6-months postintervention. The primary outcome is pain-related disability 1-week postintervention using the Brief Pain Inventory Pain Interference subscale. Secondary outcome measures include behavioral measures of functional activity, social participation, physical activity, and sleep. Determinants of treatment effect, including pain-related psychological measures, posture and movement, self-efficacy, treatment expectancy, and therapeutic alliance, will be included in the secondary moderation and mediation analyses. IMPACT: This clinical trial will provide information on the extent to which an adapted CBPT hybrid telerehabilitation intervention is effective in reducing pain-related disability for Latino patients with chronic spine pain. This information will be useful for clinicians to integrate in their practice, given the growing population of Latino patients who experience disparities in health care management of chronic pain.

Factors associated with satisfaction with physical therapy services - a survey of patients with musculoskeletal pain at a federally qualified health center.

PURPOSE: The objective of this cross-sectional survey-based study was to assess factors associated with patient satisfaction with physical therapy (PT) services received at a Federally Qualified Health Center (FQHC) in the United States (US) located near the US-Mexico border. METHODS: Patients > 18 years of age, English or Spanish speakers, referred to PT were invited to complete an online survey. Factors that may influence PT satisfaction were examined for patients who attended PT. Variables associated with PT satisfaction from bivariate analyses (p < .15) were included in three separate ordinal logistic regression models. RESULTS: Patients (N = 231) who reported more confidence that PT could help relieve their pain were more likely to have higher levels of satisfaction with PT communication, treatment, and outcomes than those who reported low confidence (p < .05). Patients who reported having more support from family and friends were more likely to have higher levels of satisfaction with PT communication and treatment than those with less support (p < .01). Patients with occasional or frequent pain after ending PT treatment were more likely to have lower satisfaction with PT outcomes than those reporting no pain (p < .05). CONCLUSIONS: Findings suggest that addressing confidence in PT and promoting health support from family and friends may be important for satisfaction with PT. Additionally, PTs may consider addressing gaps between expected and achieved outcomes to improve PT satisfaction.

Kinematic and kinetic factors associated with leg reach asymmetry during the Star Excursion Balance Test in division I athletes.

OBJECTIVES: To explore which balance and movement factors contribute most to reach distance asymmetry during the Star Excursion Balance Test (SEBT) in Division I athletes. DESIGN: Cross-Sectional Study. SETTING: Rehabilitation Biomechanics Laboratory, NCAA Division I Athletics Program. PARTICIPANTS: 36 Division I athletes (20 Male; 16 Female). MAIN OUTCOME MEASURES: Center of Pressure, Kinematic and Kinetic variables were measured during performance of anterior, Posterior-Medial (PM), and Posterior-Lateral (PL) directions of the SEBT in order to determine which factors predict reach distance asymmetry. RESULTS: COP variables approached significance in predicting asymmetry for the anterior direction (p <0.08), kinematic variables approached significance in predicting asymmetry in the PL direction (p < 0.06), and kinetic variables were significant in predicting asymmetry in the PM direction (p < 0.03). CONCLUSIONS: Findings suggest that different strategies could be used to improve leg reach asymmetry based on specific direction of the asymmetry. Improving ability to control COP area seems to be important for the anterior direction, while control of limb movement seems to be most important for leg reach asymmetry in the PM and PL directions.

Lumbar spine angles and intervertebral disc characteristics with end-range positions in three planes of motion in healthy people using upright MRI.

Understanding changes in lumbar spine (LS) angles and intervertebral disc (IVD) behavior in end-range positions in healthy subjects can provide a basis for developing more specific LS models and comparing people with spine pathology. The purposes of this study are to quantify 3D LS angles and changes in IVD characteristics with end-range positions in 3 planes of motion using upright MRI in healthy people, and to determine which intervertebral segments contribute most in each plane of movement. Thirteen people (average age = 24.4 years, range 18-51 years; 9 females; BMI = 22.4 ±â€¯1.8 kg/m2) with no history of low back pain were scanned in an upright MRI in standing, sitting flexion, sitting axial rotation (left, right), prone on elbows, prone extension, and standing lateral bending (left, right). Global and local intervertebral LS angles were measured. Anterior-posterior length of the IVD and location of the nucleus pulposus was measured. For the sagittal plane, lower LS segments contribute most to change in position, and the location of the nucleus pulposus migrated from a more posterior position in sitting flexion to a more anterior position in end-range extension. For lateral bending, the upper LS contributes most to end-range positions. Small degrees of intervertebral rotation (1-2°) across all levels were observed for axial plane positions. There were no systematic changes in IVD characteristics for axial or coronal plane positions.

Differences in symmetry of lumbar region passive tissue characteristics between people with and people without low back pain.

BACKGROUND: Several investigators have suggested that passive tissue characteristics of the lumbar region may be altered in people with low back pain. Passive stiffness of the lumbar region has been examined during physiological movements in healthy individuals and intersegmental spine mobility and stiffness have been examined in people with and people without low back pain. However, no investigators have examined differences in passive tissue characteristics of the lumbar region during a physiological movement between people with and people without low back pain. METHODS: Subjects were moved passively through a trunk lateral bending motion on a passive movement device. Lumbar region kinematics were measured with a motion capture system and force required to move the subject was measured with a force transducer. Lumbar region extensibility was defined as the maximum excursion of the lumbar region. Passive elastic energy was defined as the area under the torque-lumbar region angle curve. Differences in lumbar region extensibility and passive elastic energy between sides were examined in people with and people without low back pain (n=41). FINDINGS: People in the Rotation with Extension low back pain subgroup demonstrated greater asymmetry of passive elastic energy than people without low back pain (P=0.04). There were no differences between groups in symmetry of lumbar region extensibility (P=0.37). INTERPRETATION: Asymmetry in passive elastic energy of the lumbar region may be related to the low back pain problem in the Rotation with Extension subgroup. The asymmetry in passive elastic energy may be associated with asymmetry of loading on the spine, which has been reported to be a risk factor for low back pain. Thus, it may be important to consider the asymmetry when planning an intervention strategy for people in the Rotation with Extension subgroup.

Patterns of lumbar region movement during trunk lateral bending in 2 subgroups of people with low back pain.

BACKGROUND AND PURPOSE: The movement system impairment (MSI) system is one proposed system for classifying low back pain (LBP) problems. Prior clinical data and observations for the MSI system suggest that different LBP subgroups demonstrate different patterns of movement during clinical tests, such as trunk lateral bending (TLB). The purpose of this study, therefore, was to examine the validity of the observation that lumbar region (LR) movement patterns during TLB are different between 2 subgroups of people with LBP: lumbar rotation with extension (Rotation With Extension) and lumbar rotation (Rotation). SUBJECTS: Participants were 44 people (28 men and 16 women; age [X+/-SD], 28.5+/-8.4 years) with chronic or recurrent LBP. METHODS: Each participant's LBP problem was classified with the MSI system. Kinematic variables were measured, and LBP symptoms were recorded during the TLB test. RESULTS: People in the 2 LBP subgroups demonstrated different patterns of LR movement during TLB. People in the Rotation With Extension subgroup displayed an asymmetric (right versus left) pattern of LR movement across the TLB movement, whereas people in the Rotation subgroup displayed a symmetric pattern of LR movement. Equal proportions of people in the 2 subgroups reported an increase in symptoms with the TLB test. DISCUSSION AND CONCLUSION: The patterns of LR movement across the TLB movement were different in 2 subgroups of people with LBP. The difference in the LR movement patterns between subgroups may be an important factor to consider in specifying the details of the interventions for these 2 LBP problems.

Differences in lumbar spine and lower extremity kinematics during a step down functional task in people with and people without low back pain.

BACKGROUND: When functional movements are impaired in people with low back pain, they may be a contributing factor to chronicity and recurrence. The purpose of the current study was to examine lumbar spine, pelvis, and lower extremity kinematics during a step down functional task between people with and without a history of low back pain. METHODS: A 3-dimensional motion capture system was used to analyze kinematics during a step down task. Total excursion of the lumbar spine, pelvis, and lower extremity segments in each plane were calculated from the start to end of the task. Separate analysis of variance tests (α=0.05) were conducted to determine the effect of independent variables of group and plane on lumbar spine, pelvis, and lower extremity kinematics. An exploratory analysis was conducted to examine kinematic differences among movement-based low back pain subgroups. FINDINGS: Subjects with low back pain displayed less lumbar spine movement than controls across all three planes of movement (P-values=0.001-0.043). This group difference was most pronounced in the sagittal plane. For the lower extremity, subjects with low back pain displayed more frontal and axial plane knee movement than controls (P-values=0.001). There were no significant differences in kinematics among movement-based low back pain subgroups. INTERPRETATION: People with low back pain displayed less lumbar region movement in the sagittal plane and more off-plane knee movements than the control group during a step down task. Clinicians can use this information when assessing lumbar spine and lower extremity movement during functional tasks, with the goal of developing movement-based interventions.

Biopsychosocial risk factors associated with chronic low back pain after lower limb amputation.

Low back pain is a common secondary health condition after lower limb amputation with important implications related to functional capabilities and overall quality of life. Despite the high prevalence of low back pain after lower limb amputation, the underlying etiologies of the disorder remain unknown. This hypothesis-driven communication provides evidence in support of using the multifactorial, biopsychosocial model of low back pain experience in the general population for identification of potential risk factors and rehabilitation targets for low back pain after lower limb amputation. Key findings that link biological, psychological, and social factors and the experience of low back pain in the general patient population with LBP are discussed while highlighting gaps in our current state of knowledge related to the association of these factor and presence of low back pain after lower limb amputation. Importantly, the aim of this communication was not to propose a new model, but rather to organize data originating from prior work into a coherent hypothesis-driven conceptual framework to better understand the need for multifaceted and multidisciplinary intervention approaches for effective treatment of low back pain after lower limb amputation.

Differences in kinematics of the lumbar spine and lower extremities between people with and without low back pain during the down phase of a pick up task, an observational study.

BACKGROUND: Limited research exists on lumbar spine and lower extremity movement during functional tasks in people with and without low back pain (LBP). OBJECTIVE: To determine differences in lumbar spine and lower extremity kinematics in people with and without LBP during the down phase of a pick up task. DESIGN: Cross-sectional, observational study. METHOD: 35 people (14 M, 21 F, 26.9 ± 10.9 years, 24.8 ± 3.2 kg/m2); 18 with and 17 without LBP were matched based on age, gender and BMI. Kinematics of the lumbar spine and lower extremities were measured using 3D motion capture, while subjects picked up an object off the floor. People with LBP were examined and assigned to movement-based LBP subgroups. Repeated measures ANOVA tests were conducted to determine the effect of group and region on lumbar spine and lower extremity kinematics. A secondary analysis was conducted to examine the effect of LBP subgroup on lumbar spine kinematics. RESULTS: Compared to controls, subjects with LBP displayed greater upper and less lower lumbar flexion (P < 0.05), and more lumbar flexion during the first 25% of the pick up task (P < 0.01). There were no group differences in frontal or axial plane lumbar spine kinematics. Subjects with LBP displayed more frontal plane movement at the knee than control subjects (P < 0.01). There were no significant effects of movement-based LBP subgroup on kinematics (P > 0.05). CONCLUSIONS: When evaluating movement during a functional task, the clinician should consider regional differences in the lumbar spine, pattern of movement, and lower extremity movement.

Effect of body mass index on patient outcomes of surgical intervention for the lumbar spine.

BACKGROUND: Conflicting findings exist on the effect of obesity on outcomes of lumbar spine surgery; results depend on the diagnosis studied, procedure evaluated, definition of obesity, and specific outcomes measured. The purpose of this retrospective cohort study is to examine the effect of increasing body mass index (BMI) on surgical-related, health-related, and long-term outcomes of lumbar spine surgery in a single representative patient sample. METHODS: Using a surgical registry from an integrated health care system, 8,049 instrumented lumbar spine cases were identified between 1/1/2009 and 09/30/2013. The sample was stratified into five BMI categories. Outcomes of interest included: (I) surgical-related factors and complications; (II) health-related complications; and (III) long-term complications. Mixed linear models, conditional logistic regressions, and survival analysis using a Cox regression model were conducted controlling for surgeon effects. Age, gender, diabetes status, smoking status, admitting diagnosis, and surgical approach were included as covariates. RESULTS: Every 5 kg/m2 increase in BMI was associated with a significant increase in surgical time (7.8 minutes), estimated blood loss (EBL) (36.5 mL), risk of deep infection (OR =1.7 times), and deep vein thrombosis (DVT) (OR =1.5). BMI was not associated with increased incidence of other intraoperative or health-related complications. Rate of re-operation was 1.1 times higher with every 5 kg/m2 increase in BMI, but rate of re-operation due to adjacent segment disease (ASD) was not associated with BMI. CONCLUSIONS: Obesity had an adverse effect on certain surgical-related, health-related and long-term surgical outcomes. The magnitude of this effect increased with increasing levels of obesity, which increases the medical burden associated with obesity.

Lumbar spine postures in Marines during simulated operational positions.

Low back pain has a 70% higher prevalence in members of the armed forces than in the general population, possibly due to the loads and positions soldiers experience during training and combat. Although the influence of heavy load carriage on standing lumbar spine posture in this population is known, postures in other operationally relevant positions are unknown. Therefore, the purpose of this study was to characterize the effect of simulated military operational positions under relevant loading conditions on global and local lumbar spine postures in active duty male US Marines. Secondary objectives were to evaluate if intervertebral disc degeneration and low back pain affect lumbar spine postures. Magnetic resonance images were acquired on an upright scanner in the following operational positions: Natural standing with no external load, standing with body armor (11.3 kg), sitting with body armor, and prone on elbows with body armor. Custom software was used to measure global lumbar spine posture: Lumbosacral flexion, sacral slope, lordosis, local measures of intervertebral angles, and intervertebral distances. Sitting resulted in decreased lumbar lordosis at all levels of the spine except L1-L2. When subjects were prone on elbows, a significant increase in local lordosis was observed only at L5-S1 compared with all other positions. Marines with disc degeneration (77%) or history of low back pain (72%) had decreased lumbar range of motion and less lumbar extension than healthy Marines. These results indicate that a male Marine's pathology undergoes a stereotypic set of postural changes during functional tasks, which may impair performance. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2145-2153, 2017.

Contribution of Lumbar Spine Pathology and Age to Paraspinal Muscle Size and Fatty Infiltration.

STUDY DESIGN: Retrospective chart analysis of 199 individuals aged 18 to 80 years scheduled for lumbar spine surgery. OBJECTIVE: The purpose of this study was to quantify changes in muscle cross-sectional area (CSA) and fat signal fraction (FSF) with age in men and women with lumbar spine pathology and compare them to published normative data. SUMMARY OF BACKGROUND DATA: Pathological changes in lumbar paraspinal muscle are often confounded by age-related decline in muscle size (CSA) and quality (fatty infiltration). Individuals with pathology have been shown to have decreased CSA and fatty infiltration of both the multifidus and erector spinae muscles, but the magnitude of these changes in the context of normal aging is unknown. METHODS: Individuals aged 18 to 80 years who were scheduled for lumbar surgery for diagnoses associated with lumbar spine pain or pathology were included. Muscle CSA and FSF of the multifidus and erector spinae were measured from preoperative T2-weighted magnetic resonance images at the L4 level. Univariate and multiple linear regression analyses were performed for each outcome using age and sex as predictor variables. Statistical comparisons of univariate regression parameters (slope and intercept) to published normative data were also performed. RESULTS: There was no change in CSA with age in either sex (P > 0.05), but women had lower CSAs than men in both muscles (P < 0.0001). There was an increase in FSF with age in erector spinae and multifidus muscles in both sexes (P < 0.0001). Multifidus FSF values were higher in women with lumbar spine pathology than published values for healthy controls (P = 0.03), and slopes tended to be steeper with pathology for both muscles in women (P < 0.08) but not in men (P > 0.31). CONCLUSION: Lumbar muscle fat content, but not CSA, changes with age in individuals with pathology. In women, this increase is more profound than age-related increases in healthy individuals. LEVEL OF EVIDENCE: 3.

Gender differences in pattern of hip and lumbopelvic rotation in people with low back pain.

BACKGROUND: Findings from previous studies suggest gender may affect the pattern of hip and lumbopelvic motion during a multi-segmental movement. To date, no studies have examined movement patterns and low back pain symptom behavior during hip lateral rotation. METHODS: Forty-six people (27 males and 19 females) with low back pain were examined. Three-dimensional kinematic data and low back pain symptoms were recorded during active hip lateral rotation. Percent of maximum lumbopelvic rotation was calculated for each 10% increment of maximum active hip lateral rotation. FINDINGS: Men exhibited a greater percent of maximum lumbopelvic rotation (mean 49.3, SD 13.3) during the first 60% of hip lateral rotation than women (mean 36.2, SD 16.4) (P < 0.01). Nineteen (70.4%) of the men and seven (36.8%) of the women had pain with the hip lateral rotation test (P = 0.02). INTERPRETATION: Men exhibited more lumbopelvic rotation in the early part of hip lateral rotation than women, and hip lateral rotation was more likely to be associated with symptoms in men than women. Greater lumbopelvic motion, earlier in hip lateral rotation, may make men more vulnerable to low back pain associated with hip lateral rotation. Factors that contribute to these gender differences should be investigated further.