Sara P. Gombatto

Lumbar spine kinematics during walking in people with and people without low back pain

Low back pain (LBP) is a problem that can contribute to functional limitations and disability. Understanding kinematics during walking can provide a basis for examination and treatment in people with LBP. Prior research related to kinematics during walking is conflicting. However, investigators have not considered regional differences in lumbar spine kinematics or movement-based LBP subgroups. In the current study, three-dimensional kinematics of the upper and lower lumbar regions were examined in people with and without LBP. A clinical examination then was conducted to assign people with LBP to a movement-based subgroup and differences in kinematics among subgroups were examined. All subjects displayed significantly more upper than lower lumbar movement in the axial and coronal planes (P<.01). People with LBP displayed significantly less overall lumbar rotation than controls (P<.05). There were no significant group differences in sagittal plane kinematics (P>.05). Walking was limited by or provocative of pain in <25% of subjects with LBP. There were predictable differences in kinematics among some movement-based LBP subgroups that approached statistical significance (P=.09-.11). Walking was provocative of LBP in few subjects, and differences between people with and without LBP and among LBP subgroups were minimal. Limitations include that attempts to standardize gait speed may have minimized observed effects, and there was limited power to detect movement-based LBP subgroup differences.

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

Spine Kinematics During Prone Extension in People With and Without Low Back Pain and Among Classification-Specific Low Back Pain Subgroups

Study Design Cross-sectional observational design. Background Spine extension is used in physical therapy during examination and treatment for low back pain (LBP). However, kinematics during prone extension have not been examined using 3-D motion capture. Objectives The primary purpose was to determine differences in spine kinematics during prone extension between subjects with and without LBP. An exploratory analysis was conducted to examine kinematic differences among LBP subgroups. Methods Kinematics of the thoracic and lumbar spine were examined during prone extension, using optical motion capture, in 18 subjects with LBP and 17 subjects without LBP (control group). Excursion of each spinal region was calculated for the entire movement and during 25% increments of extension movement duration. Subjects with LBP were examined and assigned to subgroups using 3 different classification systems for LBP. Repeated-measures analysis-of-variance tests were used to examine effects of group (LBP, control), spine region, and increment of movement duration, and to explore effects of LBP subgroup. Results For spine kinematics, there was a significant group-by-region interaction effect (P<.05). Subjects with LBP displayed less lower lumbar extension (13.3° ± 4.9°) than control subjects (21.4° ± 9.2°). The majority of lower lumbar extension occurred during the first 50% of the motion for subjects with LBP. Subgroup-by-region interaction effects were significant for 2 of 3 LBP classification systems (P<.05). Conclusion Subjects with LBP displayed less lower lumbar extension than control subjects during prone extension. These differences should be considered when evaluating and prescribing prone extension. The interpretation of subgroup differences with prone extension kinematics is limited in the current study by the small sample size, but may need to be considered in future studies of spine kinematics. Level of Evidence Diagnosis, level 4. J Orthop Sports Phys Ther 2016;46(7):571-579. Epub 12 May 2016. doi:10.2519/jospt.2016.6159.

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.

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.

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 Marines pathology undergoes a stereotypic set of postural changes during functional tasks, which may impair performance.

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 (&agr; = 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. HighlightsLow back pain group displays less sagittal lumbar movement during a step down task.Low back pain group displays more frontal and axial plane movement at the knee joint.Important to examine low back and lower extremity movement during functional tasks in people with low back pain.Differences in functional movements among movement‐based low back pain subgroups should be examined further.

Diagnostic Labels Assigned to Patients With Orthopedic Conditions and the Influence of the Label on Selection of Interventions: A Qualitative Study of Orthopaedic Clinical Specialists

Background A variety of diagnostic classification systems are used by physical therapists, but little information about how therapists assign diagnostic labels and how the labels are used to direct intervention is available. Objective The purposes of this study were: (1) to examine the diagnostic labels assigned to patient problems by physical therapists who are board-certified Orthopaedic Clinical Specialists (OCSs) and (2) to determine whether the label influences selection of interventions. Design A cross-sectional survey was conducted. Methods Two written cases were developed for patients with low back and shoulder pain. A survey was used to evaluate the diagnostic label assigned and the interventions considered important for each case. The cases and survey were sent to therapists who are board-certified OCSs. Respondents assigned a diagnostic label and rated the importance of intervention categories for each case. Each diagnostic label was coded based on the construct it represented. Percentage responses for each diagnostic label code and intervention category were calculated. Relative importance of intervention category based on diagnostic label was examined. Results For the low back pain and shoulder pain cases, respectively, “Combination” (48.5%, 34.9%) and “Pathology/Pathophysiology” (32.7%, 57.3%) diagnostic labels were most common. Strengthening (85.9%, 98.1%), stretching (86.8%, 84.9%), neuromuscular re-education (87.6%, 93.4%), functional training (91.4%, 88.6%), and mobilization/manipulation (85.1%, 86.8%) were considered the most important interventions. Relative importance of interventions did not differ based on diagnostic label (χ2=0.050–1.263, P=.261–.824). Limitations The low response rate may limit the generalizability of the findings. Also, examples provided for labels may have influenced responses, and some of the label codes may have represented overlapping constructs. Conclusions There is little consistency with which OCS therapists assign diagnostic labels, and the label does not seem to influence selection of interventions.

A sensor cluster to monitor body kinematics

Several different factors have been proposed to contribute to the development of chronic low back pain (LBP). Specifically, researchers and clinicians have proposed that impairments of low back posture and movement, particularly during functional activities, are important to address during intervention. However, objective measures of posture and movement are typically only measured in the laboratory setting. Observation of posture and movement in laboratory is limited because people with LBP may not perform naturally when they are being observed, and observation in a single session does not provide information about the duration of postures or frequency of movements across the day. In this paper, we present a wireless body sensor cluster formed by up to seven sensors in order to monitor spine posture and movement both in absolute and relative coordinate systems. The Body Kinematics Monitoring (BKM) system measures the magnitude and frequency of spine movements, and duration of spine postures in 3D, without impeding natural movement. The BKM node developed in this study is 3.0cm in diameter, and contains a 9-axis motion processor that records the raw inertial information of different spine regions. The system offers a standard Bluetooth Low Energy (BLE) protocol to communicate with mobile or fixed hosts. The BKM system has been validated in the laboratory by measuring lumbar spine postures on a mechanical spine testing platform across a known range of angles.