Spinal Stiffness Research Articles

Spinal biomechanical properties are significantly altered with a novel embalming method

In vitro tests on the biomechanical properties of human spines are often performed using fresh frozen specimens. However, this carries the risk of pathogen transfer from specimen to the worker and the specimens can only be used for a limited amount of time. Human spinal specimens embalmed with formaldehyde carry an almost absent risk of transfer of pathogens and can be stored and used for a long time, but the tissue properties are strongly affected making this method inapplicable for biomechanical testing. In this study, a new embalming technique called Fix for Life (F4L), which claims to preserve the tissue properties, was tested. The range of motion (ROM) and stiffness of six fresh human spinal specimens was measured using a spinal motion simulator before and after F4L embalming. After F4L embalming, spinal stiffness increased in flexion-extension by 230%, in lateral bending by 284% and in axial rotation by 271%. ROM decreased by 46% in flexion-extension, 56% in lateral bending and 54% in axial rotation. In conclusion, based on this study, F4L does not maintain physiological spinal biomechanical properties, and we propose that this method should not be used for biomechanical studies. Nevertheless, the method may be an alternative to formaldehyde fixation in situations such as training and education because the effect on spinal biomechanics is less detrimental than formaldehyde and tissue color is maintained.

Analysis of the upper cervical spine stiffness during axial rotation: A comparative study among patients with tension-type headache or migraine and asymptomatic subjects

BackgroundMany studies reported the implication of the cervical musculoskeletal system in patients with tension type headache and migraine. The objective of this study is to investigate the upper cervical spine stiffness features in axial rotation among headache patients in comparison with a healthy population. Methods48 subjects including 30 migraine patients with/without aura and 18 patients with tension-type headache, aged between 18 and 60years (mean 36, SD 11years) have been evaluated. Stiffness measurements were carried out for passive axial rotation using a torque meter device. The flexion-rotation test was used to emphasize assessment of the upper cervical spine. FindingsNeither the stiffness nor the neutral zone varies between different populations studied. Passive range of motion in axial rotation is unilaterally reduced in symptomatic subjects (p=0.001). Considering the elastic zone, right and left motion magnitude was significantly lower for clinical groups compared to the control group. InterpretationStiffness seems not to be altered among tension type headache and migraine patients. However, patients seem prone to display a larger right-left asymmetry of axial rotation and a reduction in the motion range tolerance, emphasizing the likely link between the cervical discomfort and these pathologies. Any difference is observed in the elastic behavior of the upper cervical spine between the two primary headache populations. However, further investigations are needed to confirm these previous results taking various specific clinical characteristics into consideration.

Sleep quality, sleeping postures, and sleeping equipment in patients with ankylosing spondylitis

Background/aim: Inflammatory back pain, spinal stiffness, and limited spinal mobility are characteristic features of ankylosing spondylitis (AS). Sleeping postures can affect and/or reflect sleeping disturbances. The aim of the study was to evaluate sleeping postures and sleep disturbances in patients with AS. Materials and methods: Seventy-seven patients with AS and 49 healthy controls were enrolled. The Pittsburgh Sleep Quality Index (PSQI) and the Insomnia Severity Index (ISI) were applied to both groups. The most common sleeping postures were noted. Results: There was no significant difference between the groups in terms of sleeping postures. Total PSQI and ISI scores were higher in the AS group than in the controls (P = 0.004 and P = 0.038, respectively). The selection of sleeping postures of active and inactive patients were similar. The number of pillows used was not the same in the AS and control groups (P = 0.016). The frequency of customized bed use was higher in the AS group compared to the control group (P = 0.004). Conclusion: Sleep disturbances are more of a problem in patients with AS compared to healthy patients and in active AS patients compared to inactive ones. However, sleeping postures do not seem to affect either sleep disturbances or disease activity in patients with AS.

An unusual cause of chronic low back pain: ochronosis.

A 45-year-old man presented with low back pain evolving since 8 years associated sometimes with a radicular radiation. The clinical examination found a patient in good general condition, a loss of the lumbar lordosis, an exaggeration of the dorsal kyphosis with stiffness of the lumbar spine. The cutaneous-mucosal examination showed a brownish appearance of the ears, conjunctiva, and lower eyelids. In biology there was neither inflammatory syndrome nor perturbation of the phosphocalcic balance. The standard radiographs of the lumbar spine (A) and dorsal spine (B) revealed multiple disc calcifications associated with large staggered disc clumps and discal empty images. Due to mucocutaneous signs, normality of biology and the radiological aspect, the diagnosis of ochronosis was suspected and confirmed by the test of blackening of the urine to the ambient air, the results of the cutaneous biopsy showed pigmented deposits yellow ocher and brownish in the dermis and the dosage of alkaptonuria. Symptomatic treatment resulted in moderate improvement. The family survey did not reveal any similar cases. Ochronosis or alkaptonuria is a rare autosomal recessive disorder of tyrosine metabolism. Deficiency of homogentisate 1,2 dioxygenase results in accumulation of oxidized homogentisic acid in the connective tissues of the skin, eyes and ears, musculoskeletal system, and cardiac valves, and in urolithiasis. Ochronosis is of late onset, responsible for the rachis of extended disc calcifications with maximum spinal fusion. It is the cause of degenerative arthropathy. Early diagnosis and screening of this disease are then of great interest, especially for genetic counseling.

Diagnosis and Treatment of Inflammatory Joint Disease.

Arthritis damages the cartilage within joints, resulting in degenerative changes, including loss of function and joint instability. Ankylosing spondylitis (AS) is a chronic inflammatory condition affecting the spine and bone-to-tendon attachment area within the sacroiliac joint leading to back pain and progressive spinal stiffness. In the final stages, AS causes hyperkyphosis-a condition closely tied to the human leukocyte antigen-B27 gene. Rheumatoid arthritis is a chronic, systemic autoimmune disease characterized by the simultaneous inflammation of the synovium of multiple joints, leading to joint damage (e.g., destruction, deformation and disability). In the past, nonsteroidal anti-inflammatory drugs or conventional disease-modifying antirheumatic drug (DMARDs) have been used for the treatment of these autoimmune diseases, but biologic DMARDs have recently been introduced with excellent results. Gout is a chronic inflammatory disease that causes an alteration of joints resulting in severe pain. Specifically, gout is associated with an accumulation of uric acid within the body resulting from dysregulated purine metabolism, causing recurrent paroxysmal inflammation in the joints. Allopurinol and febuxostat are the primary treatment options for individuals with gout. It is necessary to have an accurate understanding of the pathogenesis, pathological ecology and treatment of AS, rheumatoid arthritis, and gouty arthritis, which are the representative diseases that may cause inflammatory arthritis.

Mechanisms of changes in the human spinal column in response to static and dynamic axial mechanical loading

The study was concerned with the human spinal column reaction to axial static and dynamic loading. Fresh segments of the column from dorsal vertebra XI to lumber vertebra II were exposed to axial static (20 mm/min) and dynamic (200 and 500 mm/min) loading. Measured variables included load value, whole segment deformation, anterior surfaces of intervertebral disk Th(XI)-Th(XII) and dorsal vertebra XII, and acoustic emission signals indicative of spongy bone microdestruction. It was found that vertebral body deformation augmented less in comparison with the intervertebral disk and that central parts of the spinal end plates compress greater than peripheral. This difference was more considerable due to static loading rather than dynamic. To produce deformation of a spinal segment by dynamic loading same as by the static one, it is necessary to overcome a stronger resistance of a larger number of trabecular bones. Herefrom it follows that, first, to cause an equal segment compression the dynamic load must be heavier than static and, which is of paramount practical significance, dynamic strength of the column is markedly higher than static. Secondly, spinal stiffness during impact is higher as compared with the static condition. Thirdly, same degree of deformation due to dynamic loading should result in a larger volume of microdestructions comparing with static loading, which is testified by a reliable difference in the number of AE signals accumulated prior to fracture. The number of AE signals amounts to 444.2 ± 308.2 and 85.0 ± 36.6 in case of the dynamic and static loading, respectively (p < 0.05 according to Student's t-criterion).

Dynamic characteristics and stability criterion of rotary galloping gait with an articulated passive spine joint

Based on the simplified planar quadruped model with a passive spine joint, this paper focuses on studying the effect of the spine joint on the dynamic performance and the stability of the rotary galloping gait. The stable, periodic, and symmetric rotary galloping gait is achieved by the particle swarm optimization method without any parameter symmetry for leg motion and without any limitation for spine motion. By analyzing the symmetric pattern of the rotary galloping gait, the stability criterion is derived: the closer to zero is the pitching angle at peak time of the center of mass, the better is the stability of the galloping gait. Then, we study the effect of rear leg touchdown angle and spine stiffness on the stability. Moreover, the unstable rotary galloping gait can be stabilized by adjusting one or more of the touchdown angle, spine stiffness, and leg stiffness. Furthermore, the effect of the spine stiffness on the key kinematic and kinetic properties is also studied for different initial values and mechanical parameters. The presented stability criterion and the achieved dynamic performance analysis results will be instructive for the design and control of the quadruped robot.

A new method to approximate load–displacement relationships of spinal motion segments for patient-specific multi-body models of scoliotic spine

Load-displacement relationships of spinal motion segments are crucial factors in characterizing the stiffness of scoliotic spine models to mimic the spine responses to loads. Although nonlinear approach to approximation of the relationships can be superior to linear ones, little mention has been made to deriving personalized nonlinear load-displacement relationships in previous studies. A method is developed for nonlinear approximation of load-displacement relationships of spinal motion segments to assist characterizing in vivo the stiffness of spine models. We propose approximation by tangent functions and focus on rotational displacements in lateral direction. The tangent functions are characterized using lateral bending test. A multi-body model was characterized to 18 patients and utilized to simulate four spine positions; right bending, left bending, neutral, and traction. The same was done using linear functions to assess the performance of the proposed tangent function in comparison with the linear function. Root-mean-square error (RMSE) of the displacements estimated by the tangent functions was 44% smaller than the linear functions. This shows the ability of our tangent function in approximation of the relationships for a range of infinitesimal to large displacements involved in the spine movement to the four positions. In addition, the models based on the tangent functions yielded 67, 55, and 39% smaller RMSEs of Ferguson angles, locations of vertebrae, and orientations of vertebrae, respectively, implying better estimates of spine responses to loads. Overall, it can be concluded that our method for approximating load-displacement relationships of spinal motion segments can offer good estimates of scoliotic spine stiffness.

Quantitative evaluation of the occupant kinematic response of the THUMS 50th-percentile male model relative to PMHS laboratory rollover tests

ABSTRACTObjective: The objective of the current study was to evaluate the whole-body kinematic response of the Total Human Model for Safety (THUMS) occupant model in controlled laboratory rollover tests by comparing the model response to postmortem human surrogate (PMHS) kinematic response targets published in 2014.Methods: A computational model of the parametric vehicle buck environment was developed and the AM50 THUMS occupant model (Ver 4.01) was subjected to a pure dynamic roll at 360°/s in trailing-side front-row seating position.A baseline configuration was defined by a baseline posture representing the average of all PMHS postures, with a friction coefficient of 0.4 for the belt and 0.6 for the seat.To encompass challenges in controlling boundary conditions from the PMHS tests and ensure the robustness of the model evaluation, a total of 12 simulations were performed to investigate the following:1. The effect of initial posture by adding 3 additional postures representing PMHS extremes.2. The effect of belt tension by varying tension from the nominal vehicle retractor belt tension of 5 N to the 35 N belt tension used in the PMHS tests.3. The effect of friction between the environment (belt, seat) and THUMS.Trajectories (head, T1, T4, T10, L1, and sacrum), spinal segment rotations (head-to-T1, T1-to-T4, T4-to-T10, T10-to-L1, and L1-to-sacrum) relative to the rollover buck and spinal segment elongation/compression calculated from the simulations were compared to PMHS corridors using a correlation method (CORA).Results: THUMS baseline response showed lower correlation (overall CORA score = 0.63) with the PMHS response in rollover compared to other crash modes. THUMS and PMHS demonstrated similar kinematic responses in the longitudinal axis and vertical axis but significantly different lateral excursion relative to the seat. In addition, no spinal elongation was observed for THUMS compared to the PMHS.The posture, pretension, and belt frictions were found to alter model kinematics, especially on THUMS lateral axis motion. The posture was judged to be the most sensitive parameter evaluated because a change of 30 mm in the lateral axis results in up to an 80 mm of change in observed displacement.Conclusions: Though the model response in the lateral axis is significantly different than that of the PMHS, it is unclear whether this difference is the result of extrinsic factors (posture, pretension, and friction), where exact values in experiment are unknown or by model intrinsic factors (e.g., spine stiffness). These differences in occupant kinematics could potentially subject the PMHS and THUMS to very different loading conditions under roof impact in rollover crashes: different occupant posture and different roof impact location. Therefore, different injury mechanisms and severity might be predicted by the current model relative to the PMHS. Consequently, though the information provided in the current study could be useful for improving model biofidelity for rollover crashes, additional studies are required to properly solve this issue.

Baclofen in the Therapeutic of Sequele of Traumatic Brain Injury: Spasticity.

Traumatic brain injury (TBI) is an alteration in brain function, caused by an external force, which may be a hit on the skull, rapid acceleration or deceleration, penetration of an object, or shock waves from an explosion. Traumatic brain injury is a major cause of morbidity and mortality worldwide, with a high prevalence rate in pediatric patients, in which treatment options are still limited, not available at present neuroprotective drugs. Although the therapeutic management of these patients is varied and dependent on the severity of the injury, general techniques of drug types are handled, as well as physical and surgical. Baclofen is a muscle relaxant used to treat spasticity and improve mobility in patients with spinal cord injuries, relieving pain and muscle stiffness. Pharmacological support with baclofen is contradictory, because disruption of its oral administration may cause increased muscle tone syndrome and muscle spasm, prolonged seizures, hyperthermia, dysesthesia, hallucinations, or even multisystem organ failure. Combined treatments must consider the pathophysiology of broader alterations than only excitation/inhibition context, allowing the patient's reintegration with the greatest functionality.

Effect of follower load on motion and stiffness of the human thoracic spine with intact rib cage

Researchers have reported on the importance of the rib cage in maintaining mechanical stability in the thoracic spine and on the validity of a compressive follower preload. However, dynamic mechanical testing using both the rib cage and follower load has never been studied. An in vitro biomechanical study of human cadaveric thoracic specimens with rib cage intact in lateral bending, flexion/extension, and axial rotation under varying compressive follower preloads was performed. The objective was to characterize the motion and stiffness of the thoracic spine with intact rib cage and follower preload. The hypotheses tested for all modes of bending were (i) range of motion, elastic zone, and neutral zone will be reduced with a follower load, and (ii) neutral and elastic zone stiffness will be increased with a follower load. Eight human cadaveric thoracic spine specimen (T1–T12) with intact rib cage were subjected to 5Nm pure moments in lateral bending, flexion/extension, and axial rotation under follower loads of 0–400N. Range of motion, elastic and neutral zones, and elastic and neutral zone stiffness values were calculated for functional spinal units and segments within the entire thoracic section. Combined segmental range of motion decreased by an average of 34% with follower load for every mode. Application of a follower load with intact rib cage impacts the motion and stiffness of the human cadaveric thoracic spine. Researchers should consider including both aspects to better represent the physiologic implications of human motion and improve clinically relevant biomechanical thoracic spine testing.

Does experimental low back pain change posteroanterior lumbar spinal stiffness and trunk muscle activity? A randomized crossover study

BackgroundWhile some patients with low back pain demonstrate increased spinal stiffness that decreases as pain subsides, this observation is inconsistent. Currently, the relation between spinal stiffness and low back pain remains unclear. This study aimed to investigate the effects of experimental low back pain on temporal changes in posteroanterior spinal stiffness and concurrent trunk muscle activity. MethodIn separate sessions five days apart, nine asymptomatic participants received equal volume injections of hypertonic or isotonic saline in random order into the L3–L5 interspinous ligaments. Pain intensity, spinal stiffness (global and terminal stiffness) at the L3 level, and the surface electromyographic activity of six trunk muscles were measured before, immediately after, and 25-minute after injections. These outcome measures under different saline conditions were compared by generalized estimating equations. FindingsCompared to isotonic saline injections, hypertonic saline injections evoked significantly higher pain intensity (mean difference: 5.7/10), higher global (mean difference: 0.73N/mm) and terminal stiffness (mean difference: 0.58N/mm), and increased activity of four trunk muscles during indentation (P<0.05). Both spinal stiffness and trunk muscle activity returned to baseline levels as pain subsided. InterpretationWhile previous clinical research reported inconsistent findings regarding the association between spinal stiffness and low back pain, our study revealed that experimental pain caused temporary increases in spinal stiffness and concurrent trunk muscle co-contraction during indentation, which helps explain the temporal relation between spinal stiffness and low back pain observed in some clinical studies. Our results substantiate the role of spinal stiffness assessments in monitoring back pain progression.

Restoring lumbar spine stiffness using an interspinous implant in an ovine model of instability

BackgroundThe objective of this study was to determine the effect of an interspinous implant on lumbar spine stability and stiffness during dorsoventral loading. MethodsTwelve Merino lambs were mechanically tested in vivo. Oscillatory (2Hz) loads were applied to L2 under load control while displacements were monitored. Tri-axial accelerometers further quantified adjacent L3–L4 accelerations. Dorsoventral lumbar spine stiffness and L3 and L4 dorsoventral and axial displacements were determined over six trials of 20cycles of loading. Four conditions were examined: 1) initial intact, 2) following destabilization at L3–L4, 3) following the insertion of an InSwing® interspinous device at L3–L4, and 4) with the implant secured with a tension band. Comparisons were performed using a one-way ANOVA with repeated measures and post-hoc Bonferroni correction. FindingsCompared to the intact condition, destabilization significantly decreased lumbar stiffness by 4.5% (P=.001) which was only recovered by the interspinous device with tension band. The interspinous device caused a significant 9.75% (P=.001) increase in dorsoventral stiffness from destabilization that increased 14% with the tension band added (P=.001). The tension band was responsible for decreased displacements from the intact (P=.038), instability (P=.001), and interspinous device (P=.005) conditions. Dorsoventral L3–L4 motion significantly improved with the interspinous device (P=.01) and the addition of the tension band (P=.001). No significant differences in L3–L4 intersegmental stability were noted for axial motion in the sagittal plane. InterpretationThis ovine model provided objective in vivo biomechanical evidence of lumbar instability and its restoration by means of an interspinous implant during dorsoventral spinal loading.

Sagittal rotational stiffness and damping increase in a porcine lumbar spine with increased or prolonged loading

While the impact of load magnitude on spine dynamic parameters (stiffness and damping) has been reported, it is unclear how load history (exposure to prolonged loading) affects spine dynamic parameters in sagittal rotation. Furthermore, it is unknown if both spine stiffness and damping are equally affected to prolonged loading. Using a pendulum testing apparatus, the effect of load magnitude and load history on spine sagittal rotational stiffness and damping was assessed. Nine porcine lumbar functional spine units (FSUs) were tested in an increasing compressive load phase (ICP: 44.85, 68.55, 91.75, 114.6kg) and then a decreasing compressive load phase (DCP: 91.75, 68.55, and 44.85kg). Each trial consisted of flexing the FSU 5° and allowing it to oscillate unconstrained. During the ICP, both stiffness and damping linearly increased with load. However, in the DCP, stiffness and damping values were significantly higher than the identical load collected during the ICP, suggesting load history affects sagittal rotational dynamic parameters. In addition, spine damping was more affected by load history than spine stiffness. These results highlight the importance of controlling load magnitude and history when assessing spine dynamic parameters.

Mechanism of Action of Spinal Mobilizations: A Systematic Review.

Systematic review. To review the evidence regarding the mechanism of action of mobilizations. Spinal mobilizations-low velocity passive oscillatory movements-reduce spinal pain in some patient subgroups. Identifying patients likely to respond remains a challenge since mobilizations' mechanism(s) of action are unclear. Medline, Web of Science, Cinahl, Embase, and Scopus databases were searched for relevant studies. Reference lists of included studies were hand searched. Studies were included if the intervention was passive spinal mobilizations, participants were symptomatic, and outcomes evaluated possible mechanisms of action. Methodological quality was independently assessed by two assessors using a modified Cochrane Back Review Group tool. Twenty-four studies were included in the review. Four were classified high risk, 14 moderate risk, and four low risk of bias. Commonest methodological limitations were lack of participant blinding, adequate randomization and allocation concealment, and sample size calculation. Evidence suggests that spinal mobilizations cause neurophysiological effects resulting in hypoalgesia (local and/or distal to mobilization site), sympathoexcitation, and improved muscle function. Mobilizations have no effect on temperature pain threshold. Three of four studies reported reduction in spinal stiffness, heterogeneous in location and timing. There is limited evidence (one study in each case) to suggest that mobilizations produce increased nociceptive flexion reflex threshold, improved posture, decreased concentration of substance P in saliva, and improved sway index measured in cervical extension. Evidence does not support an effect on segmental vertebral movement. Two studies investigated correlations between hypoalgesia and mechanism: one found a correlation with sympathoexcitatory changes, whereas the other found no correlation with change in stiffness. These findings suggest involvement of an endogenous pain inhibition system mediated by the central nervous system, although this is yet to be investigated directly. There is limited evidence regarding other possible mechanisms. 3.

Quantification of the upper cervical spine stiffness among headache patients

Quantification of the upper cervical spine stiffness among headache patients

Posterior-anterior(PA) pressure Puffin for measuring and treating spinal stiffness: Mechanism and repeatability

BackgroundPosterior–anterior (PA) pressure technique is widely used for assessing and treating spinal segments. PA pressure is manually applied and stiffness is subjectively assessed. The method has been deemed unreliable and is associated with occupational strain. ObjectivesTo introduce a new ergonomically designed hand-held device measuring spinal stiffness, and to assess its repeatability. DesignQuasi experimental study. MethodA convenience sample of 30 university students, 20–30 years old was used. The participants were tested two consecutive days by two physical therapy students using the new device; the PA pressure Puffin. The spinal segments under study were L1, Th12, Th7 and Th6 which all were tested three times with 9 kg force by both testers, both days. Intra-class correlation coefficients (ICC3,k) were used to assess intra- and inter-tester repeatability and analysis of variance with alpha-level at 0.05 was used to assess differences in joint mobility at the four segments measured. Linear regression analyses were used to assess repeatability. ResultsInter-tester and intra-tester coefficients (ICCs) ranged from 0.88 to 0.97 and from 0.83 to 0.97, respectively. There was no significant difference in displacement between Th6 and Th7 but all other joints were significantly different from each other. Displacement was always significantly greater the second day compared with day one (p < 0.05). ConclusionsThis close to final prototype of the PA pressure Puffin measures segmental spinal stiffness and its ergonomically designed handle provides a promising tool for physical therapists applying PA pressure. Further research is needed for validation and reliability assessments.

Dynamic, six-axis stiffness matrix characteristics of the intact intervertebral disc and a disc replacement.

Thorough pre-testing is critical in assessing the likely in vivo performance of spinal devices prior to clinical use. However, there is a lack of data available concerning the dynamic testing of lumbar (porcine model) total disc replacements in all six axes under preload conditions. The aim of this study was to provide new data comparing porcine lumbar spinal specimen stiffness between the intact state and after the implantation of an unconstrained total disc replacement, in 6 degrees of freedom. The dynamic, stiffness matrix testing of six porcine lumbar isolated disc specimens was completed using triangle waves at a test frequency of 0.1 Hz. An axial preload of 500 N was applied during all testing. Specimens were tested both in the intact condition and after the implantation of the total disc replacement. Sixteen key stiffness terms were identified for the comparison of the intact and total disc replacement specimens, comprising the 6 principal stiffness terms and 10 key off-axis stiffness terms. The total disc replacement specimens were significantly different to the intact specimens in 12 of these key terms including all six principal stiffness terms. The implantation of the total disc replacement resulted in a mean reduction in the principal stiffness terms of 100%, 91%, and 98% in lateral bending, flexion-extension, and axial rotation, respectively. The novel findings of this study have demonstrated that the unconstrained, low-friction total disc replacement does not replicate the stiffness of the intact specimens. It is likely that other low-friction total disc replacements would produce similar results due to stiffness being actively minimised as part of the design of low-friction devices, without the introduction of stiffening elements or mechanisms to more accurately replicate the mechanical properties of the natural intervertebral disc. This study has demonstrated, for the first time, a method for the quantitative comparative mechanical function testing of total disc replacements and provides baseline data for the development of future devices.

Functional Limitations Due to Lumbar Stiffness in Adults With and Without Spinal Deformity.

Cross-sectional analysis. To compare Lumbar Stiffness Disability Index (LSDI) scores between asymptomatic adults and patients with spinal deformity. The LSDI was designed and validated as a tool to assess functional impacts of lumbar spine stiffness and diminished spinal flexibility. Baseline disability levels of patients with adult spinal deformity (ASD) are high as measured by multiple validated outcome tools. Baseline lumbar stiffness-related disability has not been assessed in adults with and without spinal deformity. The LSDI and Scoliosis Research Society-22r (SRS-22r) were submitted to a group of asymptomatic adult volunteers. Additionally, a multicenter cross-sectional cohort analysis of patients with ASD from 10 centers was conducted. Baseline LSDI and SRS-22r were completed for both operatively and nonoperatively treated patients with deformity. The LSDI was completed by 176 asymptomatic volunteers and 693 patients with ASD. Mean LSDI score for asymptomatic volunteers was 3.4 +/- 6.3 out of a maximum score of 100, with significant correlation between increasing age and higher (worse) LSDI score (r = 0.30, P = 0.0001). Of the patients with spinal deformity undergoing analysis, 301 subsequently underwent surgery and 392 were subsequently treated nonoperatively. Operative patients had significantly higher preoperative LSDI scores than both nonoperative patients and asymptomatic volunteers (29.9 vs. 17.3 vs. 3.4, P < 0.0001 for both). For patients with ASD, significant correlations were found between LSDI and SRS-22 Pain and Function subscales (r = -0.75 and -0.76, respectively; P < 0.0001 for both). LSDI scores are low among asymptomatic volunteers, although stiffness-related disability increases with increasing age. Patients with ASD report substantial stiffness-related disability even prior to surgical fusion. Stiffness-related disability correlates with pain- and function-related disability measures among patients with spinal deformity.

Fusionless surgery in early-onset scoliosis

BackgroundSurgical treatment of early-onset scoliosis has greatly developed in recent years. Early-onset scoliosis covers a variety of etiologies (idiopathic, neurologic, dystrophic, malformative, etc.) with onset before the age of 5 years. Progression and severity threaten respiratory development and may result in respiratory failure in adulthood. Many surgical techniques have been developed in recent years, aiming to protect spinal and thoracic development. Material and methodsPresent techniques are based on one of two main principles. The first consists in posterior distraction of the spine in its concavity (single growing rod, or vertical expandable prosthetic titanium rib [VEPTR]), or on either side (dual rod); this requires iterative surgery, for lengthening, unless motorized using energy provided by a magnetic system. The second option is to use spinal growth force to lengthen the assembly; these techniques (Luque Trolley, Shilla), using a sliding assembly, are known as growth guidance. ResultsThese techniques are effective in controlling early scoliotic deformity, and to some extent restore spinal growth. However, they show a high rate of complications: infection, rod breakage, spinal fixation pull out and, above all, progressive spinal stiffness, reducing long-term efficacy. Respiratory gain is harder to assess, as thoracic expansion does not systematically improve respiratory function, particularly due to impaired compliance of the thoracic cage.