Evaluation of a Chair-Mounted Passive Trunk Orthosis: A Pilot Study on Able-Bodied Subjects

Trunk stability is important for adequate arm function due to their kinematic linkage. People with Duchenne muscular dystrophy (DMD) can benefit from trunk-assistive devices for seated daily activities, but existing devices limit trunk movement to forward bending. We developed a new trunk orthosis that has spring and pulley design. This study evaluated orthosis performance with 40 able-bodied subjects under with and without orthosis condition in 20 seated tasks for trunk rotation, forward bending, and side bending movements. Subjects adopted static posture in specific trunk orientation while their muscle activity was recorded. They also rated the subjective scales of perceived exertion and usability. A percent change in muscle activity for each task, due to orthosis use, is reported. Significant muscle activity reductions up to 31% and 65% were observed in lumbar and thoracic erector spinae muscles, respectively. Using three-way ANOVA, we found these reductions to be specific to the task direction and the choice of upper limb that is used to perform the asymmetric tasks. A total of 70% participants reported acceptable usability and ~1-point increase in exertion was found for maximum voluntary reaching with the orthosis. The outcomes of this study are promising, though tested on able-bodied subjects. Hence, orthosis mounted on wheelchairs should be further evaluated on DMD patients.

Adolescent Idiopathic Scoliosis Treated by Posterior Spinal Segmental Instrumented Fusion : When Is Fusion to L3 Stable?

Objective : The purpose of this study was to identify risk factors for distal adding on (AO) or distal junctional kyphosis (DJK) in adolescent idiopathic scoliosis (AIS) treated by posterior spinal fusion (PSF) to L3 with a minimum 2-year follow-up.Methods : AIS patients undergoing PSF to L3 by two senior surgeons from 2000–2010 were analyzed. Distal AO and DJK were deemed poor radiographic results and defined as >3 cm of deviation from L3 to the center sacral vertical line (CSVL), or >10° angle at L3–4 on the posterior anterior- or lateral X-ray at ultimate follow-up. New stable vertebra (SV) and neutral vertebra (NV) scores were defined for this study. The total stability (TS) score was the sum of the SV and NV scores.Results : Ten of 76 patients (13.1%) were included in the poor radiographic outcome group. The other 66 patients were included in the good radiographic outcome group. Lower Risser grade, more SV-3 (CSVL doesn’t touch the lowest instrumented vertebra [LIV]) on standing and side bending films, lesser NV and TS score, rigid L3–4 disc, more rotation and deviation of L3 were identified risk factors for AO or DJK. Age, number of fused vertebrae, curve correction, preoperative coronal/sagittal L3–4 disc angle did not differ significantly between the two groups. Multiple logistic regression results indicated that preoperative Risser grade 0, 1 (odds ratio [OR], 1.8), SV-3 at L3 in standing and side benders (OR, 2.1 and 2.8, respectively), TS score -5, -6 at L3 (OR, 4.4), rigid disc at L3–4 (OR, 3.1), LIV rotation >15° (OR, 2.9), and LIV deviation >2 cm from CSVL (OR, 2.2) were independent predictive factors. Although there was significant improvement of the of Scoliosis Research Society-22 average scores only in the good radiographic outcome group, there was no significant difference in the scores between the groups.Conclusion : The prevalence of AO or DJK at ultimate follow-up for AIS with LIV at L3 was 13.1%. To prevent AO or DJK following fusion to L3, we recommend that the CSVL touch L3 in both standing and side bending, TS score is -4 or less, the L3/4 disc is flexible, L3 is neutral (<15°) and ≤2 cm from the midline and the patient is ≥ Risser 2.

Combination of Side-Bending and Traction Radiographs Do Not Influence Selection of Fusion Levels Compared to Either One Alone in Adolescent Idiopathic Scoliosis

Study Design: A retrospective study. Objectives: Curve flexibility in patients with adolescent idiopathic scoliosis (AIS) can be evaluated using different techniques. This study aimed to determine whether the combination of side-bending (SB) and traction (TX) radiographs influences preoperative planning for AIS than either radiograph alone. Methods: Thirty-two spine surgeons were asked to review 30 AIS Lenke type 1 cases and select an upper instrumented vertebra (UIV) and lower instrumented vertebra (LIV) for the posterior spinal instrumentation of each case. Each rater reviewed the cases 3 times in each round. The raters were provided with the full-length posteroanterior (PA) and lateral standing and SB radiographs for round 1; PA, lateral, and TX radiographs for round 2; and PA, lateral, SB, and TX radiographs for round 3. Intra- and inter-rater reliabilities were evaluated using Kappa statistics. Results: The intra-rater reliability for UIV and LIV was 0.657 and 0.612 between rounds 1 and 2, 0.634 and 0.692 between rounds 1 and 3, and 0.659 and 0.638 between rounds 2 and 3, respectively, which indicated substantial agreement between rounds. The inter-rater kappa reliabilities for UIV and LIV selection were 0.103 and 0.412 for round 1, 0.121 and 0.380 for round 2, and 0.125 and 0.368 for round 3, indicating slight to moderate agreement between raters. Conclusions: Whether raters used either SB or TX radiography, or both in addition to PA and lateral standing radiographs, did not influence the decision making for UIV or LIV of AIS Lenke type 1 surgery.

Development of an Imaging Evaluation System for Low Back Pain

Purpose To design a low back pain (LBP) imaging evaluation system for non-professional operators, quantifying risk of LBP in patients and asymptomatic individuals. Methods Twenty-one previously asymptomatic subjects and five LBP patients diagnosed by a physician performed a series of test movements under a fixed camera, including hip abduction test, forward bending test, side bending test, double legs lowering test (DLLT), and modified Thomas test. The video clips were analyzed by a system program interface and were classified into a score from 1 to 4. The average total scores of the two groups were compared. Five intact subjects were retested to verify reliability. Twelve intact subjects and three patients’ clips were viewed by an experienced therapist to verify system validity. Results The average total scores of two groups were significantly different (p = 0.0004). The results of hip abduction test, forward bending test, side bending test and DLLT showed significant differences between the two groups. The total score of two trials in the retest experiment exhibited a similar result (p = 0.058), with good linear correlation (r = 0.98). The total scores of the evaluations by the experienced therapist and the system program interface agreed with each other (p = 0.141; linear correlation r = 0.90). Conclusion The evaluation system showed potential utility in screening LBP risk, with acceptable test–retest reliability and expert validity.

Supine Traction Versus Prone Bending Radiographs for Assessing the Curve Flexibility in Spinal Deformity

Study Design: Retrospective cohort study. Objectives: No consensus exists among surgeons on which radiologic method to prefer for the assessment of curve flexibility in spinal deformity. The objective of this study was to evaluate the difference in curve correction on supine traction radiographs versus prone side bending radiographs. Methods: A retrospective analysis of idiopathic scoliosis (IS), degenerative idiopathic scoliosis (DIS) and de novo degenerative lumbar scoliosis (DNDLS) patients was performed on supine traction as well as prone bending films (when available). Age, weight, traction force, diagnosis and Cobb angles of the primary and secondary curves were extracted. Differences in curve correction (percentages) on traction versus prone bending radiographs were analyzed for the primary and secondary curve. Subgroup analyses were performed for the 3 different diagnoses. Results: In total, 170 patients were eligible for inclusion. 43 were diagnosed with IS, 58 with DIS and 69 with DNDLS. For the primary curve, greater curve correction was obtained with bending in the DNDLS group ( P < 0.001). In the DIS group, there was a trend toward more correction on bending ( P = 0.054). In de IS group no difference was found. For the secondary curve, bending showed more curve correction in the IS and DIS group ( P = 0.002 and P <0.001). No difference was found in the DNDLS group. Conclusion: Compared to traction radiographs, bending radiographs better serve the purpose of curve flexibility assessment of IS, DIS and DNDLS spinal deformity, despite the fact that patients are exposed to more radiation.

Impact of Supine Radiographs to Assess Curve Flexibility in the Treatment of Adolescent Idiopathic Scoliosis

Study Design: Retrospective cohort study. Objectives: The purpose of the study is to evaluate the role of supine radiographs in determining flexibility of thoracic and thoracolumbar curves. Methods: Ninety operative AIS patients with 2-year follow-up from a single institution were queried and classified into MT structural and TL structural groups. Equations were derived using linear regression to compute cut-off values for MT and TL curves. Thresholds were externally validated in a separate database of 60 AIS patients, and positive and negative predictive values were determined for each curve. Results: MT supine values were highly predictive of MT side-bending values (TL group: 0.63, P < 0.001; MT group: 0.66, P = 0.006). Similarly, TL supine values were highly predictive of TL side-bending values (TL group: 0.56, P = 0.001 MT group: 0.68, P = 0.001). From our derived equations, MT and TL curves were considered structural on supine films if they were ≥ 30° and 35°, respectively. Contingency table analysis of external validity sample showed that supine films were highly predictive of structurality of MT curve (Sensitivity = 0.91, PPV = 0.95, NPV = 0.81) and TL curve (Sensitivity = 0.77, PPV = 0.81, NPV = 0.94). ROC analysis revealed that the area under curve for MT structurality from supine films was 0.931 (SEM: 0.03, CI: 0.86-0.99, P < 0.001) and TL structurality from supine films was 0.922 (SEM: 0.03, CI- 0.84-0.98, P < 0.001). Conclusions: A single preoperative supine radiograph is highly predictive of side-bending radiographs to assess curve flexibility in AIS. A cut-off of ≥ 30° for MT and ≥ 35° for TL curves in supine radiographs can determine curve structurality.

Effects of the Manual Therapy Approach of Segments C0-1 and C2-3 in the Flexion-Rotation Test in Patients with Chronic Neck Pain: A Randomized Controlled Trial

Background: Flexion-rotation test predominantly measures rotation in C1-2 segment. Restriction in flexion-rotation may be due to direct limitation in C1-2, but also to a premature tightening of the alar ligament as a result of lack of movement in C0-1 or C2-3. The aim of this study was to compare the effect of a 20-min single cervical exercise session, with or without manual therapy of C0-1 and C2-3 segment in flexion-rotation test, in patients with chronic neck pain and positive flexion-rotation test. Methods: Randomized controlled clinical trial in 48 subjects (24 manual therapy+exercise/24 exercise). Range of motion and pain during flexion-rotation test, neck pain intensity and active cervical range of motion were measured before and after the intervention. Results: Significant differences were found in favour of the manual therapy group in the flexion-rotation test: right (p < 0.001) and left rotation (p < 0.001); pain during the flexion-rotation test: right (p < 0.001) and left rotation (p < 0.001); neck pain intensity: (p < 0.001); cervical flexion (p < 0.038), extension (p < 0.010), right side-bending (p < 0.035), left side-bending (p < 0.002), right rotation (p < 0.001), and left rotation (p < 0.006). Conclusions: Addition of one C0-C1 and C2-C3 manual therapy session to cervical exercise can immediately improve flexion-rotation test and cervical range of motion and reduce pain intensity.

Analytical model for determining allowances for elastomer constrained bending of aircraft parts

In the article, the authors present a method of constrained bending of aircraft sheet parts with curved sides by an elastic medium. The process of conducting constrained bending is described. A schematic description of the process is presented. The manufacture of a part is carried out in two steps. As a result of the first step, a piece is obtained with thinning in the radius part, the second step is accomplished with a unit die of reduced height. The resulting wave of excess material is deformed along the radius of the bending mandrel. In the finished part, an increase in the thickness of the workpiece is observed in the zone of the bending radius. The wave of excess material is formed due to a special allowance, the size of which is the critical factor for achieving this increase in thickness. The analytical model for determining the allowance is based on generally accepted assumptions and principles for calculating process parameters. To determine the allowance, an approximation of the shape of the excess wave by a tangential function is proposed. This allows you to get an analytical dependence that relates the geometry of the part and the thickening of the wall to the size of the allowance. The size of the allowance is limited to a certain range, the lower boundary of which is determined by the onset of plastic deformations, the upper one - by the possibility of loss of stability, leading to irreparable spoilage. The results are illustrated by graphs of the dependence of the minimum and maximum allowance for the side height on the ratios of the workpiece wall thickness, the radius of the side bending and the radius of the side in plan. Characteristic curves and analytical dependencies are presented in a dimensionless form, where the geometric parameters are assigned to the radius of the bending tool, that is, to the radius of bending of the part side on the inner surface.

Effect of ice massage with integrated neuromuscular inhibition technique on pain and function in subjects with mechanical neck pain: randomized controlled trial

Background Myofascial trigger point (MTrP) plays a major role in the genesis of mechanical neck pain, which may lead to chronic disorders. The purpose of the study is to investigate and compare the effect of ice massage plus integrated neuromuscular inhibition technique (INIT) versus INIT alone on active trigger points in the upper trapezius of persons having mechanical neck pain. Forty participants diagnosed as mechanical neck pain with upper trapezius active myofascial trigger points. They were randomized into two equal groups. Group A (experimental) received ice massage for 10 min plus INIT, while group B (control) received INIT alone. The treatment program continued for 2 weeks (3 sessions/week). The outcome measures are the pain intensity, pain pressure threshold, cervical lateral side bending and neck daily functions. Results The results showed that there were significant improvements in VAS at p = .899 and F = .78, PPT at p = .288 and F = .553, cervical side bending at p = .094 and F < 0.00001, and NDI at p = .164 and F = 0.00001 in both groups, while there were no statistically significant differences between both groups as p > 0.05. Conclusion Ice massage and INIT are effective methods in managing active trigger points in the upper trapezius of persons having mechanical neck pain without statistically significant difference.

Influence of Rib Cage on Static Characteristics of Scoliotic Spine

Background. Scoliosis is a three-dimensional (3D) deformity of the spine, which affects the patient’s appearance and may lead to abnormal heart and lung function. The rib cage is a structure composed of ribs, sternum, and costal cartilage, which plays a vital role in stabilising the thoracolumbar spine. This study investigates the influence of the rib cage on the static characteristics of the scoliotic spine. Methods. Two types of 3D finite element (FE) models with or without rib cage (from T1 to S) were established and analysed based on computed tomography (CT) images, to determine the effects of the rib cage on the static characteristics of the scoliotic spine. The FE software, ABAQUS, was used to analyse the static behaviours of scoliotic spine models under a range of loading conditions, including left side bending, right side bending, front tilt, rear supine, and vertical compression. The changes in the von Mises stress (VMS) within the intervertebral discs of spine models with or without rib cage were studied and compared. Results. After including the rib cage, the maximum VMS at the stress concentrations of the normal and scoliotic spine effectively reduced. The VMS in normal intervertebral discs was gentler than that of scoliotic ones. However, the scoliotic spine was more likely to produce large stress concentration in the intervertebral discs of scoliotic segments. Conclusions. Under the common postures, intervertebral discs of scoliotic segments are more susceptible to generate stress concentrations compared with the normal spine. The rib cage could effectively keep the intervertebral discs of scoliotic segments from further injuries. These results are of great significance for the prevention and treatment of the scoliotic spine.