Bone strain index as a predictor of further vertebral fracture in osteoporotic women: An artificial intelligence-based analysis

BACKGROUND

Osteoporosis is an asymptomatic disease of high prevalence and incidence, leading to bone fractures burdened by high mortality and disability, mainly when several subsequent fractures occur. A fragility fracture predictive model, Artificial Intelligence-based, to identify dual X-ray absorptiometry (DXA) variables able to characterise those patients who are prone to further fractures called Bone Strain Index, was evaluated in this study.

METHODS

In a prospective, longitudinal, multicentric study 172 female outpatients with at least one vertebral fracture at the first observation were enrolled. They performed a spine X-ray to calculate spine deformity index (SDI) and a lumbar and femoral DXA scan to assess bone mineral density (BMD) and bone strain index (BSI) at baseline and after a follow-up period of 3 years in average. At the end of the follow-up, 93 women developed a further vertebral fracture. The further vertebral fracture was considered as one unit increase of SDI. We assessed the predictive capacity of supervised Artificial Neural Networks (ANNs) to distinguish women who developed a further fracture from those without it, and to detect those variables providing the maximal amount of relevant information to discriminate the two groups. ANNs choose appropriate input data automatically (TWIST-system, Training With Input Selection and Testing). Moreover, we built a semantic connectivity map usingthe Auto Contractive Map to provide further insights about the convoluted connections between the osteoporotic variables under consideration and the two scenarios (further fracture vs no further fracture).

RESULTS

TWIST system selected 5 out of 13 available variables: age, menopause age, BMI, FTot BMC, FTot BSI. With training testing procedure, ANNs reached predictive accuracy of 79.36%, with a sensitivity of 75% and a specificity of 83.72%. The semantic connectivity map highlighted the role of BSI in predicting the risk of a further fracture.

CONCLUSIONS

Artificial Intelligence is a useful method to analyse a complex system like that regarding osteoporosis, able to identify patients prone to a further fragility fracture. BSI appears to be a useful DXA index in identifying those patients who are at risk of further vertebral fractures.

A neck compression injury criterion incorporating lateral eccentricity

There is currently no established injury criterion for the spine in compression with lateral load components despite this load combination commonly contributing to spinal injuries in rollover vehicle crashes, falls and sports. This study aimed to determine an injury criterion and accompanying tolerance values for cervical spine segments in axial compression applied with varying coronal plane eccentricity. Thirty-three human cadaveric functional spinal units were subjected to axial compression at three magnitudes of lateral eccentricity of the applied force. Injury was identified by high-speed video and graded by spine surgeons. Linear regression was used to define neck injury tolerance values based on a criterion incorporating coronal plane loads accounting for specimen sex, age, size and bone density. Larger coronal plane eccentricity at injury was associated with smaller resultant coronal plane force. The level of coronal plane eccentricity at failure appears to distinguish between the types of injuries sustained, with hard tissue structure injuries more common at low levels of eccentricity and soft tissue structure injuries more common at high levels of eccentricity. There was no relationship between axial force and lateral bending moment at injury which has been previously proposed as an injury criterion. These results provide the foundation for designing and evaluating strategies and devices for preventing severe spinal injuries.

An improved spinal injury parameter model for underbody impulsive loading scenarios

Underbody blast events such as aircraft ejection, mine blast, and helicopter crashes pose a serious threat to occupants. These impulsive excitations exert substantial axial loads on the thoracolumbar spine causing severe injuries. The Dynamic Response Index (DRI), which is commonly used as the injury parameter for underbody loading scenarios, suffers from inherent disadvantages and has been reported to underpredict the chances of injury. The main reasons are the inability of the DRI model to account for bending loads and posture of the spine. Thus, a novel lumped full spine model capable of modelling the spine in different posture along the sagittal plane is formulated. The unavailable data for the model were obtained using inverse parameter identification approach by eigenfrequency matching. Each vertebra has three degrees of freedom: axial, shear, and rotary motion to model the flexion of the spine. A new injury parameter is proposed based on the sum of compressions caused due to axial and rotary springs at each vertebral level, to account for wedge compression and burst fractures. The results indicate that the model was able to predict the motions of vertebrae under different postures of the spine according to trends in literature.

Musculoskeletal modelling of the human cervical spine for the investigation of injury mechanisms during axial impacts

Head collisions in sport can result in catastrophic injuries to the cervical spine. Musculoskeletal modelling can help analyse the relationship between motion, external forces and internal loads that lead to injury. However, impact specific musculoskeletal models are lacking as current viscoelastic values used to describe cervical spine joint dynamics have been obtained from unrepresentative quasi-static or static experiments. The aim of this study was to develop and validate a cervical spine musculoskeletal model for use in axial impacts. Cervical spine specimens (C2-C6) were tested under measured sub-catastrophic loads and the resulting 3D motion of the vertebrae was measured. Specimen specific musculoskeletal models were then created and used to estimate the axial and shear viscoelastic (stiffness and damping) properties of the joints through an optimisation algorithm that minimised tracking errors between measured and simulated kinematics. A five-fold cross validation and a Monte Carlo sensitivity analysis were conducted to assess the performance of the newly estimated parameters. The impact-specific parameters were integrated in a population specific musculoskeletal model and used to assess cervical spine loads measured from Rugby union impacts compared to available models. Results of the optimisation showed a larger increase of axial joint stiffness compared to axial damping and shear viscoelastic parameters for all models. The sensitivity analysis revealed that lower values of axial stiffness and shear damping reduced the models performance considerably compared to other degrees of freedom. The impact-specific parameters integrated in the population specific model estimated more appropriate joint displacements for axial head impacts compared to available models and are therefore more suited for injury mechanism analysis.

Three-dimensional kinematic corridors of the head, spine, and pelvis for small female driver seat occupants in near- and far-side oblique frontal impacts

OBJECTIVES

Analyses of recent automotive accident data indicate an increased risk of injury for small female occupants compared to males in similar accidents. Females have been shown to be more susceptible to spinal injuries than males. To protect this more vulnerable population, advanced anthropomorphic test devices (ATDs) and computer human body models are being developed and require biofidelity curves for validation. The aim of this study is to generate female-specific 3D kinematic corridors in near- and far-side oblique frontal impacts for the head, spine, and pelvis.

METHODS

Eight specimens were procured and prescreened for mass, stature, and quantitative computed tomography bone mineral density and preexisting injuries to minimize biologic variability. Sets of 4 noncolinear retroreflective targets were placed on the back of the head; dorsal spine at T1, T8, and L2; and posterior sacrum. Instrumented computed tomography scans were obtained to measure the orientation and position of the markers relative to anatomic fiducials. The specimens were placed on a buck representative of a generic automotive driver's seat environment designed to minimize lower-extremity and pelvic motion. The buck was oriented such that the buck centerline was seated 30° from the impact vector in either a near- or far-side oblique frontal configuration. Preposition of the occupant was specified to the 50th percentile male H-point location, thigh and tibial angles, and torso angle. Impact was delivered via a servo-acceleration sled to the base of the buck with a 30 km/h 9 g trapezoidal pulse. Occupants were restrained by a standard 3-point belt that had a custom load-limiter device set to 2 kN at the D-ring side of the shoulder belt. Target motion was recorded at 1 kHz using a 3D optical motion capture system. Anatomic motion of the head, spine, and pelvis was calculated relative to the seat, and the average response was determined from 4 near-side and 4 far-side tests. The borders of the corridor were determined by calculating a standard deviational ellipse in the x, y, and z planes at each time step.

RESULTS

Plots of the biofidelity corridors for near- and far-side tests are shown in planes parallel to the seat from the lateral, rear, and overhead directions. Averaged peak excursions in the fore/aft and lateral directions are compared for the near- and far-side corridors. Near-side female and male tests are similarly compared.

CONCLUSIONS

In general, average peak excursions were greater in the far-side configuration than in the near-side configuration. Peak excursion results compared well with similar tests conducted on male postmortem human subjects (PMHS). The kinematic corridors developed in the current study serve as a set of biofidelity corridors for the development of current and future physical and computational surrogates.

Thoracic and lumbar spine responses in high-speed rear sled tests

OBJECTIVE

This study analyzed thoracic and lumbar spine responses with in-position and out-of-position (OOP) seated dummies in 40.2 km/h (25 mph) rear sled tests with conventional and all-belts-to-seat (ABTS) seats. Occupant kinematics and spinal responses were determined with modern (≥2000 MY), older (<2000 MY), and ABTS seats.

METHODS

The seats were fixed in a sled buck subjected to a 40.2 km/h (25 mph) rear sled test. The pulse was a 15 g double-peak acceleration with 150 ms duration. The 50th percentile Hybrid III was lap-shoulder belted in the FMVSS 208 design position or OOP, including leaning forward and leaning inboard and forward. There were 26 in-position tests with 11 <2000 MY, 8 ≥2000 MY, and 7 ABTS and 14 OOP tests with 6 conventional and 8 ABTS seats. The dummy was fully instrumented. This study addressed the thoracic and lumbar spine responses. Injury assessment reference values are not approved for the thoracic and lumbar spine. Conservative thresholds exist. The peak responses were normalized by a threshold to compare responses. High-speed video documented occupant kinematics.

RESULTS

The extension moments were higher in the thoracic than lumbar spine in the in-position tests. For <2000 MY seats, the thoracic extension moment was 76.8 ± 14.6% of threshold and the lumbar extension moment was 50.5 ± 17.9%. For the ≥2000 MY seats, the thoracic extension moment was 54.2 ± 26.6% of threshold and the lumbar extension moment was 49.8 ± 27.7%. ABTS seats provided similar thoracic and lumbar responses. Modern seat designs lowered thoracic and lumbar responses. For example, the 1996 Taurus had -1,696 N anterior lumbar shear force and -205.2 Nm extension moment. There was -1,184 N lumbar compression force and 1,512 N tension. In contrast, the 2015 F-150 had -500 N shear force and -49.7 Nm extension moment. There was -839 N lumbar compression force and 535 N tension. On average, the 2015 F-150 had 40% lower lumbar spine responses than the 1996 Taurus. The OOP tests had similar peak lumbar responses; however, they occurred later due to the forward lean of the dummy.

CONCLUSIONS

The design and performance of seats have significantly changed over the past 20 years. Modern seats use a perimeter frame allowing the occupant to pocket into the seatback. Higher and more forward head restraints allow a stronger frame because the head, neck, and torso are more uniformly supported with the seat more upright in severe rear impacts. The overall effect has been a reduction in thoracic and lumbar loads and risks for injury.

Association between spinal immobilization and survival at discharge for on-scene blunt traumatic cardiac arrest: A nationwide retrospective cohort study

INTRODUCTION

Spinal immobilization has been indicated for all blunt trauma patients suspected of having cervical spine injury. However, for traumatic cardiac arrest (TCA) patients, rapid transportation without compromising potentially reversible causes is necessary. Our objective was to investigate the temporal trend of spinal immobilization for TCA patients and to examine the association between spinal immobilization and survival.

METHODS

We conducted a retrospective cohort study using the Japan Trauma Data Bank 2004-2015 registry data. Our study population consisted of adult blunt TCA patients encountered at the scene of a trauma. The primary outcome was the survival proportion at hospital discharge, and the secondary outcome was the proportion achieving return of spontaneous circulation (ROSC). We examined the association between spinal immobilization and these outcomes using a logistic regression model based on imputed data sets with the multiple imputation method to account for missing data.

RESULTS

Among 4313 patients who met the inclusion criteria, 3307 (76.7%) were immobilized. The proportion of patients that underwent spinal immobilization gradually decreased from 82.7% in 2004-2006 to 74.0% in 2013-2015. 1.0% of immobilized and 0.9% of non-immobilized patients had severe cervical spine injury. Spinal immobilization was significantly associated with lower survival at discharge (odds ratio [OR], 0.64; 95% confidence interval [CI], 0.42 to 0.98) and ROSC by admission (OR, 0.48; 95%CI, 0.27 to 0.87). There was no significant sub-group difference of the association between spinal immobilization and survival at discharge by patients with or without cervical spine injury (p for interaction 0.73).

CONCLUSION

Spinal immobilization is widely used even for blunt TCA patients, even though it is associated with a lower rate of survival at discharge and ROSC by admission. According to these results, we suggest that spinal immobilization should not be routinely recommended for all blunt TCA patients.

Effect of training in advanced trauma life support on the kinematics of the spine: A simulation study

More than 7.5 million people in the world are affected by spinal cord injury (SCI). In this study, we aimed to analyze the effect of training in advanced trauma life support (ATLS) on the kinematics of the spine when performing different mobilization and immobilization techniques on patients with suspected SCI. A quasi-experimental study, clinical simulation, was carried out to determine the effect of training in ATLS on 32 students enrolled in the Master's program of Emergency and Special Care Nursing. The evaluation was performed through 2 maneuvers: placing of the scoop stretcher (SS) and spinal board (SB), with an actor who simulated a clinical situation of suspected spinal injury. The misalignment of the spine was measured with the use of a Vicon 3D motion capture system, before (pre-test) and after (post-test) the training. In the overall misalignment of both maneuvers, statistically significant differences were found between the pre-test misalignment of 62.1° ± 25.9°, and the post-test misalignment of 32.3° ± 10.0°, with a difference between means of 29.7° [(95% confidence interval, 95% CI 22.8-36.6°), (P = .001)]. The results obtained for the placing of the SS showed that there was a pre-test misalignment of 65.1° ± 28.7°, and a post-test misalignment of 33.2° ± 10.1°, with a difference of means of 33.9° [(95% CI, 23.1-44.6°), (P = .001)]. During the placing of the SB, a pre-test misalignment of 59.0° ± 28.7° and a post-test misalignment of 33.4° ± 10.0° were obtained, as well as a difference of means of 25.6° [(95% CI 16.6-34.6°), (P = .001)]. The main conclusion of this study is that training in ATLS decreases the misalignment provoked during the utilization of the SS and SB, regardless of the device used.

Clinical characteristics and outcomes of treatment of the cervical spine in patients with persistent post-concussion symptoms: A retrospective analysis

BACKGROUND

Concussion is typically defined as a mild brain injury, and yet the brain is unlikely to be the only source of persistent post-concussion symptoms. Concurrent injury to the cervical spine in particular is acknowledged as a potential source of common persistent symptoms such as headache, dizziness and neck pain.

OBJECTIVES

To describe the cervical spine findings and outcomes of treatment in a series of patients with persistent post-concussion symptoms, and describe the clinical characteristics of a cervicogenic component when it is present.

DESIGN

Retrospective chart review of a consecutive series of patients with concussion referred to a physiotherapist for cervical spine assessment.

METHOD

Patient charts for all patients over a calendar year referred by a concussion service provider to a physiotherapist for cervical spine assessment were de-identified and transferred to the research team. Clinical data were independently extracted by two research assistants and analysed using descriptive statistics.

RESULTS/FINDINGS

Data were analysed from 46 patient charts. Those with a cervicogenic component (n = 32) were distinguished from those without a cervicogenic component (n = 14) by physical examination findings, particularly pain on manual segmental examination. Physiotherapy treatment of the cervicogenic component (n = 21) achieved improvements in function (mean increase of 3.8 in the patient-specific functional scale), and pain (mean decrease of 4.6 in the numeric pain-rating scale).

CONCLUSIONS

The clinical characteristics described give preliminary support to the idea that the cervical spine may contribute to persistent post-concussion symptoms, and highlight the value of physiotherapy assessment and treatment of the cervical spine following a concussive injury.

Cervical Spine Injuries: A Whole-Body Musculoskeletal Model for the Analysis of Spinal Loading

Cervical spine trauma from sport or traffic collisions can have devastating consequences for individuals and a high societal cost. The precise mechanisms of such injuries are still unknown as investigation is hampered by the difficulty in experimentally replicating the conditions under which these injuries occur. We harness the benefits of computer simulation to report on the creation and validation of i) a generic musculoskeletal model (MASI) for the analyses of cervical spine loading in healthy subjects, and ii) a population-specific version of the model (Rugby Model), for investigating cervical spine injury mechanisms during rugby activities. The musculoskeletal models were created in OpenSim, and validated against in vivo data of a healthy subject and a rugby player performing neck and upper limb movements. The novel aspects of the Rugby Model comprise i) population-specific inertial properties and muscle parameters representing rugby forward players, and ii) a custom scapula-clavicular joint that allows the application of multiple external loads. We confirm the utility of the developed generic and population-specific models via verification steps and validation of kinematics, joint moments and neuromuscular activations during rugby scrummaging and neck functional movements, which achieve results comparable with in vivo and in vitro data. The Rugby Model was validated and used for the first time to provide insight into anatomical loading and cervical spine injury mechanisms related to rugby, whilst the MASI introduces a new computational tool to allow investigation of spinal injuries arising from other sporting activities, transport, and ergonomic applications. The models used in this study are freely available at simtk.org and allow to integrate in silico analyses with experimental approaches in injury prevention.

[REACTIVITY AND RESISTANCE OF THE SPINAL STRUCTURES WHEN PERFORMING INSTRUMENTAL CORRECTION OF SPINAL DEFORMITIES]

The aim of the study was the electroneuromyographic evaluation of the spinal cord pyramidal structures reactivity and resistance in response to the impact of intraoperative factors associated with the application of technologies instrumental correction of spinal deformities of various etiologies and degrees of severity, realized with the help of submersible transpedicular fixation systems. Before treatment and 4-31 (9.6 ± 0.3) days after surgery using methods of global and stimulation (M-responses) electroneuromyography were examined 135 patients 8-50 (16.4 ± 0.6) years (42 male, 93 female) with spinal deformities of various etiologies and severity. The intrao perative maximum angle correction of the spinal column ranged from 3° to 95° (37.2 ± 1.5°). To assess the reactivity of the spinal cord structures located at the top of the primary arc deformation used integral index - the index of sensorimotor deficit (ISD). The lowest values of ISD and most distinct postoperative negative trends of this indicator were observed in persons with spinal deformities of neuromuscular etiology.

[ENTROPY MONITORING DURING LOW-FLOW INHALATION ANESTHESIA--A TRIBUTE TO FASHION OR NECESSITY?]

OBJECTIVE

To compare anesthesia quality and sevoflurane consumption during standard and extended intraoperative monitoring.

MATERIALS AND METHODS

74 patients were included in prospective randomized study. Patients had spinal pathology of varying severity, extension and localization. A comparative evaluation of standard and extended (with entropy) monitoring was performed during low-flow inhalation anesthesia with the automated control of the anesthetic concentration and exhaled oxygen fraction (Et-control).

RESULTS

Monitoring depth of anesthesia based on entropy enables more accurate dosing of inhaled anesthetics.

CONCLUSIONS

The study revealed that the use of entropy monitoring in high-risk surgery alleviates providing the controlled anesthesia with the optimal inhalation anesthetic concentration and minimal hemodynamic reactions of the patient.

Return-to-Play Recommendations After Cervical, Thoracic, and Lumbar Spine Injuries: A Comprehensive Review

CONTEXT

Currently, there is a national focus on establishing and disseminating standardized guidelines for return to play for athletes at all levels of competition. As more data become available, protocols and guidelines are being refined and implemented to assist physicians, coaches, trainers, players, and parents in making decisions about return to play. To date, no standardized criteria for returning to play exist for injuries to the spine.

EVIDENCE ACQUISITION

Electronic databases including PubMed and MEDLINE and professional orthopaedic, neurosurgical, and spine organizational websites were reviewed between 1980 and 2015.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 4.

RESULTS

Although clinical guidelines have been published for return to play after spine injury, they are almost exclusively derived from expert opinion and clinical experience rather than from well-designed studies. Furthermore, recommendations differ and vary depending on anatomic location, type of sport, and surgery performed.

CONCLUSION

Despite a lack of consensus and specific recommendations, there is universal agreement that athletes should be pain free, completely neurologically intact, and have full strength and range of motion before returning to play after spinal injury.

Biomechanical modelling of impact-related fracture characteristics and injury patterns of the cervical spine associated with riding accidents

BACKGROUND

Horse-related injuries are manifold and can involve the upper and lower limbs, the trunk, spine or head. Cervical spine injuries are not among the most common injuries. However, they can be fatal and often result in neurological symptoms. This study investigated the influence of the posture of the cervical spine on the ultimate strength and the pattern of vertebrae failure with the aim to provide some guidance for protective clothing design.

METHODS

Eighteen human cervical spines, each divided into two specimens (three vertebrae each), were subjected to a simulator test designed to mimic a spinal trauma in different postures of the specimen (neutral, flexion, extension). The stress-to-failure, the deformation at the time of fracture and the fracture patterns assessed based on CT scans were analysed.

FINDINGS

Stress-to-failure of the superior specimens was lower for the flexion group compared to the others (P=0.027). The superior specimens demonstrated higher stress-to-failure in comparison to the inferior specimens (P<0.001). Compression in a neutral or flexed position generated mild or moderate fracture patterns. On the contrary, the placement of the spine in extension resulted in severe fractures mostly associated with narrowing of the spinal canal.

INTERPRETATION

The results imply that a neutral cervical spine position during an impaction can be beneficial. In this position, the failure loads are high, and even if a vertebral fracture occurs, the generated injury patterns are expected to be mild or moderate.

Relationship Between Vertebral Fracture Burden, Height Loss, and Pulmonary Function in Postmenopausal Women With Osteoporosis

The purpose of this analysis was to assess the association of osteoporosis-related vertebral fracture burden and pulmonary function. This study also examined the relationship between vertebral fracture burden and height loss, estimated by arm span - height. This was a single-site and single-visit study. Patients had a history of at least 1 moderate or severe vertebral fracture. Vertebral fracture burden was quantified using the spinal deformity index (SDI). Pulmonary function during inspiration was determined by spirometry. Forty-one women aged 70-91 completed the study. Vertebral fracture burden negatively correlated with forced inspiratory vital capacity and inspiratory time. For each unit increase in SDI, forced inspiratory vital capacity decreased by 1.62%, and inspiratory time decreased by 2.39%. There was no correlation between SDI and measures of inspiratory flow. For each unit increase in SDI, height decreased by about 0.5 cm. Vertebral fractures were associated with decreased lung volume and height loss.

Comparison of functional network integrity in TBI and orthopedic controlpatientsusing graph-theoretical analysis

The integrity of functional brain networks inpatients (n=12) diagnosed with traumatic brain injury (TBI) was compared to age-matched subjects (n=12) with orthopedic injury (OI) during a working memory task. A graph-theoretical analysis algorithm was developed and integrated into the AFNI software. Functional networks with correlations between time courses as edge-weights were automatically created and their integrity was quantified by determining the statistical significance of the following network parameters: diameter, density, clustering coefficient, average path length, two largest eigenvalues, spectral density, and minimum eccentricity. Network graphs using a spring-embedded layout (Cytoscape) and a 3D layout integrated into the anatomical space (Paraview) were created. Functional images were composed by color-coding the degree of each voxel (network node) and transformed into Talairach space. Using the AFNI Talairach atlas, degrees of distinct brain regions were quantified. Reduced averaged BOLD responses were found for the TBI group with a higher network integrity potentially as a compensatory mechanism. Regions of high functional connectivity varied in between groups with largest differences in the cerebellum, the temporal lobes and deep brain structures including the lentiform nucleus, caudate and thalamus.

Effects of acceleration level on lumbar spine injuries in military populations

BACKGROUND CONTEXT

Clinical studies have indicated that thoracolumbar trauma occurs in the civilian population at its junction. In contrast, injury patterns in military populations indicate a shift to the inferior vertebral levels of the lumbar spine. Controlled studies offering an explanation for such migrations and the associated clinical biomechanics are sparse in literature.

PURPOSE

The goals of this study were to investigate the potential roles of acceleration loading on the production of injuries and their stability characteristics using a human cadaver model for applications to high-speed aircraft ejection and helicopter crashes.

STUDY DESIGN

Biomechanical laboratory study using unembalmed human cadaver lumbar spinal columns.

METHODS

Thoracolumbar columns from post-mortem human surrogates were procured, x-rays taken, intervertebral joints and bony components evaluated for degeneration, and fixed using polymethylmethacrylate. The inferior end was attached to a platform via a load cell and uniaxial accelerometer. The superior end was attached to the upper metal platform via a semi-circular cylinder. The pre-flexed specimen was preloaded to simulate torso mass. The ends of the platform were connected to the vertical post of a custom-designed drop tower. The specimen was dropped inducing acceleration loading to the column. Axial force and acceleration data were gathered at high sampling rates, filtered, and peak accelerations and inertia-compensated axial forces were obtained during the loading phase. Computed tomography images were used to identify and classify injuries using the three-column concept (stable vs. unstable trauma).

RESULTS

The mean age, total body mass, and stature of the five healthy degeneration-free specimens were 42 years, 73 kg, and 167 cm. The first two specimens subjected to peak accelerations of approximately 200 m/sec(2) were classified as belonging to high-speed aircraft ejection-type and the other three specimens subjected to greater amplitudes (347-549 m/sec(2)) were classified as belonging to helicopter crash-type loadings. Peak axial forces for all specimens ranged from 4.8 to 7.2 kN. Ejection-type loaded specimens sustained single-level injuries to the L1 vertebra; one injury was stable and the other was unstable. Helicopter crash-type loaded specimens sustained injuries at inferior levels, including bilateral facet dislocation at L4-L5 and L2-L4 compression fractures, and all specimens were considered unstable at least at one spinal level.

CONCLUSIONS

These findings suggest that the severity of spinal injuries increase with increasing acceleration levels and, more importantly, injuries shift inferiorly from the thoracolumbar junction to lower lumbar levels. Acknowledging that the geometry and load carrying capacity of vertebral bodies increase in the lower lumbar spine, involvement of inferior levels in trauma sparing the superior segments at greater acceleration inputs agree with military literature of caudal shift in injured levels. The present study offers an experimental explanation for the clinically observed caudal migration of spinal trauma in military populations as applied to high-speed aircraft ejection catapult and helicopter crashes.

Clinical evaluation and airway management for adults with cervical spine instability

Airway management of patients with cervical spine instability may be difficult as a result of immobilization, and may be associated with secondary neurologic injury related to cervical spine motion. Spinal cord instability is most common in patients with trauma, but there are additional congenital and acquired conditions that predispose to subacute cervical spine instability. Patients with suspected instability should receive immobilization during airway management with manual in-line stabilization. The best strategy for airway management is one that applies the technique with the highest likelihood of success on the first attempt and the lowest biomechanical influence on a potentially unstable spine.

Do you have a right to decide? Or do we have a right to acquiesce?

Clinicians make decisions about patient management on a daily basis and are required to act in a way that is both legally and ethically correct. To act legally requires compliance with a set of rules which reflect the values and interests of society. Ethical decisions are based on what we believe as a group to be morally right. Morals are, however, unique to the individual. Balancing the legal, ethical and moral dimensions of clinical decisions has the potential, therefore, to generate conflict for the individual practitioner. In this paper we report a case study of a patient with a high cervical spine injury resulting in quadriplegia, without prospect of a ventilator independent life. The patient, who was assessed as having capacity to make decisions, subsequently elected to have treatment withdrawn. In this case, withdrawal of treatment constituted removal of mechanical ventilation which ultimately resulted in death. The patient also requested for his organs to be donated after he was deceased. This case study, to our knowledge, is the first report of donation after cardiac death following a high cervical spinal injury in a cognitively intact patient. As such, this case study allows us to discuss the moral, ethical and legal implications of donation after cardiac death following withdrawal of medical treatment.

Clinical study of ganglioside (GM) combined with methylprednisolone (MP) for early acute spinal injury

This paper aims to make an analysis of the effects of ganglioside (GM) combined with methylprednisolone (MP) in early acute spinal injury. Fifty-three patients with acute spinal cord injury were included in this study and they were randomly divided into experimental and control group. Twenty-seven patients in the control group were treated with MP, while the rest 26 patients received more GM based on that. By observing and comparing the clinical responses from patients and recovery time of all indexes, results came out: the curative rates in the experimental and control group were 50.0%, 40.7% respectively, and the total effective rates were 92.3%, 85.2% respectively. There was a remarkable difference between the two groups (P<0.05). Patients in the experimental group took 6.2 ± 1.9d to restore their sphincter function, 11.2 ± 2.8d to recover their muscle forces to over grade II, and 13.8 ± 3.9d to return general activity, while the patients in the other group clearly spent longer time on recovery, that were 12.1 ± 3.2, 19.2 ± 4.6 and 23.9 ± 5.6 respectively. The distinct difference between the two groups was of statistical significance (P<0.05). We conclude that GM has better curative effects than MP, for it is able to promote the recovery of nerve function for patients and greatly improve the prognosis.

Sensitivity of head and cervical spine injury measures to impact factors relevant to rollover crashes

OBJECTIVE

Serious head and cervical spine injuries have been shown to occur mostly independent of one another in pure rollover crashes. In an attempt to define a dynamic rollover crash test protocol that can replicate serious injuries to the head and cervical spine, it is important to understand the conditions that are likely to produce serious injuries to these 2 body regions. The objective of this research is to analyze the effect that impact factors relevant to a rollover crash have on the injury metrics of the head and cervical spine, with a specific interest in the differentiation between independent injuries and those that are predicted to occur concomitantly.

METHODS

A series of head impacts was simulated using a detailed finite element model of the human body, the Total HUman Model for Safety (THUMS), in which the impactor velocity, displacement, and direction were varied. The performance of the model was assessed against available experimental tests performed under comparable conditions. Indirect, kinematic-based, and direct, tissue-level, injury metrics were used to assess the likelihood of serious injuries to the head and cervical spine.

RESULTS

The performance of the THUMS head and spine in reconstructed experimental impacts compared well to reported values. All impact factors were significantly associated with injury measures for both the head and cervical spine. Increases in impact velocity and displacement resulted in increases in nearly all injury measures, whereas impactor orientation had opposite effects on brain and cervical spine injury metrics. The greatest cervical spine injury measures were recorded in an impact with a 15° anterior orientation. The greatest brain injury measures occurred when the impactor was at its maximum (45°) angle.

CONCLUSIONS

The overall kinetic and kinematic response of the THUMS head and cervical spine in reconstructed experiment conditions compare well with reported values, although the occurrence of fractures was overpredicted. The trends in predicted head and cervical spine injury measures were analyzed for 90 simulated impact conditions. Impactor orientation was the only factor that could potentially explain the isolated nature of serious head and spine injuries under rollover crash conditions. The opposing trends of injury measures for the brain and cervical spine indicate that it is unlikely to reproduce the injuries simultaneously in a dynamic rollover test.

Dynamic Responses of Intact Post Mortem Human Surrogates from Inferior-to-Superior Loading at the Pelvis

During certain events such as underbody blasts due to improvised explosive devices, occupants in military vehicles are exposed to inferior-to-superior loading from the pelvis. Injuries to the pelvis-sacrum-lumbar spine complex have been reported from these events. The mechanism of load transmission and potential variables defining the migration of injuries between pelvis and or spinal structures are not defined. This study applied inferior-to-superior impacts to the tuberosities of the ischium of supine-positioned five post mortem human subjects (PMHS) using different acceleration profiles, defined using shape, magnitude and duration parameters. Seventeen tests were conducted. Overlay temporal plots were presented for normalized (impulse momentum approach) forces and accelerations of the sacrum and spine. Scatter plots showing injury and non-injury data as a function of peak normalized forces, pulse characteristics, impulse and power, loading rate and sacrum and spine accelerations were evaluated as potential metrics related to pathological outcomes with the focus of examining the role of the pulse characteristics from inferior-to-superior loading of the pelvis-sacrum-lumbar spine complex. Interrelationships were explored between non-fracture and fracture outcomes, and fracture patterns with a focus on migration of injuries from the hip-only to hip and spine to spine-only regions. Observations indicate that injury to the pelvis and or spine from inferior-to-superior loading is associated with pulse and not just peak velocity. The role of the effect of mass recruitment and injury migration parallel knee-thigh-hip complex studies, suggest a wider application of the recruitment concept and the role of the pulse characteristics.

Evaluation of clinical efficacy and safety of cervical trauma collars: differences in immobilization, effect on jugular venous pressure and patient comfort

BACKGROUND

Concern has been raised that cervical collars may increase intracranial pressure in traumatic brain injury. The purpose of this study was to compare four types of cervical collars regarding efficacy of immobilizing the neck, effect on jugular venous pressure (JVP), as a surrogate for possible effect on intracranial pressure, and patient comfort in healthy volunteers.

METHODS

The characteristics of four widely used cervical collars (Laerdal Stifneck(®) (SN), Vista(®) (VI), Miami J Advanced(®) (MJ), Philadelphia(®) (PH)) were studied in ten volunteers. Neck movement was measured with goniometry, JVP was measured directly through an endovascular catheter and participants graded the collars according to comfort on a scale 1-5.

RESULTS

The mean age of participants was 27 ± 5 yr and BMI 26 ± 5. The mean neck movement (53 ± 9°) decreased significantly with all the collars (p < 0.001) from 18 ± 7° to 25 ± 9° (SN < MJ < PH < VI). There was a significant increase in mean JVP (9.4 ± 1.4 mmHg) with three of the collars, but not with SN, from 10.5 ± 2.1 mmHg to 16.3 ± 3.3 mmHg (SN < MJ < VI < PH). The grade of comfort between collars varied from 4.2 ± 0.8 to 2.2 ± 0.8 (VI > MJ > SN > PH).

CONCLUSION

Stifneck and Miami J collars offered the most efficient immobilization of the neck with the least effect on JVP. Vista and Miami J were the most comfortable ones. The methodology used in this study may offer a new approach to evaluate clinical efficacy and safety of neck collars and aid their continued development.

[Calculation of the strain-deformation condition of the spinal motor segment during loading]

A mathematical model is proposed to analyze the spinal strain-deformation condition resulting from axial and lateral g-loads generated by changes in the gravity field and/or pilot's maneuvering high-performance aircraft. The solution algorithm takes into account changes in the intervertebral disk pressure and the fibrous ring shape at the time of close-to-critical g values. Calculation of the spinal strain-deformation condition was implemented by the instrumentality of computer system SPLEN (KOMMEK ltd., Russia). Analysis of the spinal strain-deformation condition was made for 2 types of external loads, i.e. normal and unilateral with a bending moment. Maximum permissible loads on a spinal segment were evaluated, as well as distribution of strain intensity, mean strains, spinal deformation and destruction field was described. The constructed computer models could be used as a basis for developing a technique of predicting characteristic spinal injuries in consequence of specific extreme loads and pathologies.

[Rehabilitative treatment of patients with complicated spinal injuries and trophic disorders in specialized neurological center]

The analysis of treatment results 132 patients with consequences with spine injury and the presence of venous disorders which in conditions of specialized health resort management system applied in complex restorative treatment, which includes patogeneti no-reasonable comprehensive preparation, surgery and further restorative treatment. Based on the analysis and systematization of the results developed diagnostic and therapeutic algorithm and algorithm for planning surgical tactics.

Motion in the unstable cervical spine when transferring a patient positioned prone to a spine board

CONTEXT

Two methods have been proposed to transfer an individual in the prone position to a spine board. Researchers do not know which method provides the best immobilization.

OBJECTIVE

To determine if motion produced in the unstable cervical spine differs between 2 prone logrolling techniques and to evaluate the effect of equipment on the motion produced during prone logrolling.

DESIGN

Crossover study.

SETTING

Laboratory.

PATIENTS OR OTHER PARTICIPANTS

Tests were performed on 5 fresh cadavers (3 men, 2 women; age = 83 ± 8 years, mass = 61.2 ± 14.1 kg).

MAIN OUTCOME MEASURE(S)

Three-dimensional motions were recorded during 2 prone logroll protocols (pull, push) in cadavers with an unstable cervical spine. Three equipment conditions were evaluated: football shoulder pads and helmet, rigid cervical collar, and no equipment. The mean range of motion was calculated for each test condition.

RESULTS

The pull technique produced 16% more motion than the push technique in the lateral-bending angulation direction (F1,4 = 19.922, P = .01, η(2) = 0.833). Whereas the collar-only condition and, to a lesser extent, the football-shoulder-pads-and-helmet condition demonstrated trends toward providing more stability than the no-equipment condition, we found no differences among equipment conditions. We noted an interaction between technique and equipment, with the pull maneuver performed without equipment producing more anteroposterior motion than the push maneuver in any of the equipment conditions.

CONCLUSIONS

We saw a slight difference in the motion measured during the 2 prone logrolling techniques tested, with less lateral-bending and anteroposterior motion produced with the logroll push than the pull technique. Therefore, we recommend adopting the push technique as the preferred spine-boarding maneuver when a patient is found in the prone position. Researchers should continue to seek improved methods for performing prone spine-board transfers to further decrease the motion produced in the unstable spine.

[Clinical features and strategies for the treatment of cervical spinal injury in aged patients]

OBJECTIVE

To investigate clinical features and treatments of cervical spinal injury in aged patients.

METHODS

From July 2006 to October 2011, 27 patients with cervical spinal cord injury were divided into experiment group, including 20 males and 7 females with an average age of 69 years old (ranged 65 to 78 years old). The other 22 patients with the same degree of cervical spianl cord injury and the same period hospitalization were chosen to regard as control group, including 16 males and 6 females with an average age of 47 years old (ranged 38 to 65 years old). All of them had clear history of trauma, and were admitted to hospital within one week. Clinical data and result of follow up were evaluated between two group. The function of the spinal cord was measured by Frankel classification at admission and final follow-up.

RESULTS

All patients were followed up for 1 year except 6 died in aged group, among which 3 paients with complications were died during hospitalization and others were out of hospital. Twenty-three cases had accompanied diseases and 24 cases occurred complications in aged group. Contrast to control group, this difference was statistically significant. At the final follow-up, there were 2 cases at Frankel grade E in aged group and 6 cases in control group.

CONCLUSION

In comparison with control group, there are more accompany diseases and higher complications and mortality rates in aged group, while poor improvement of spinal cord function. This patients were mainly treated with operation, but operation method should simplify and mainly focus on effective decompression and reconstuction stability and avoid expansion operation. It's nesscerry to pay more attention to prevent and treatment of respiratory complication.

[Algorithm of diagnostics and surgery of trauma and degenerative diseases of cervical spine]

A retrospective analysis of diagnostics and surgery in 240 patients was made. The vertebral spinal trauma took place in 168 patients (average age 31 +/- 5 years), degenerative dystrophic diseases of spine were in 72 patients (average age 52 +/- 7 years). The clinicodiagnostic complex included survey and functional radiography of the spine, magnetic resonance image and helical computer tomography of the spine with spondylometric measurements and color duplex scanning of the vertebral artery. Stabilization of the spine was performed in 137 (57%) cases. The variants were determined on the basis of predominate injury of 1 out of 3 supporting complexes. The rigid and dynamic methods and their combination were used for fixation of the spine. More favorable results were registered using dynamic fixation and the arthroplasty of intervertebral disks with nitinol constructions. An algorithm of radiodiagnostics and surgery methods were proposed.

[Cardiac pathology and autonomic dysfunction in patients with vertebral and spinal cord injury]

The disturbances of cardiovascular function were examined in 103 patients with vertebral and spinal cord injury. To evaluate myocardial conduction time and regulation of heart rate we used the method of spiroarteriocardiorythmography. Comparative power spectral and time domain analyses of heart rate variability were carried out in patient and healthy individuals. The autonomic nervous system dysfunction revealed in patients result in severe cardiovascular complications and is associated with high risk of heart diseases.

[The features of cardio-respiratory system and autonomic regulation in parasportsmen with spinal injury]

A comprehensive study of the functional state of basketball athletes in wheelchairs with spinal cord injuries in the T6-T10 and paraplegia (n = 9, mean age 26.6 +/- 1.7 years) was held. As a control, we used disability groups with a similar injury, leading an active life (n = 13, mean age 44.5 +/- 2.6 years), athletes ( = 14, mean age 24.6 +/- 1.3 years) and healthy physically active men (n = 15, the average age of 24.9 +/- 0.6 years). In the athletes in wheelchairs it was revealed an increase in the length of the body in a sitting position, the increase in tidal volume and increasing in the effectiveness of the functional respiratory tests. These changes in the state of the musculoskeletal system and autonomic systems to ensure physical activity classified as adaptive and due to sports training. In the state of the cardiovascular system and its autonomic regulation parasportsmen showed a reduction in trauma-induced increase in diastolic blood pressure and increase in the magnitude of arterial baroreflex sensitivity, decreased due to spinal injury. These data indicate availability of compensatory processes aimed at optimizing the cardiovascular system through the mechanisms of baroreflex regulation.

Mechanical failure begins preferentially near resorption cavities in human vertebral cancellous bone under compression

The amount of bone turnover in the body has been implicated as a factor that can influence fracture risk and bone strength. Here we test the idea that remodeling cavities promote local tissue failure by determining if microscopic tissue damage (microdamage) caused by controlled loading in vitro is more likely to form near resorption cavities. Specimens of human vertebral cancellous bone (L4, 7 male and 2 female, age 70±10, mean±SD) were loaded in compression to the yield point, stained for microscopic tissue damage and submitted to three-dimensional fluorescent imaging using serial milling (image voxel size 0.7×0.7×5.0 μm). We found the resulting damage volume per bone volume (DV/BV) was correlated with percent eroded surface (p<0.01, r(2)=0.65), demonstrating that whole specimen measures of resorption cavities and microdamage are related. Locations of microdamage were more than two times as likely to have a neighboring resorption cavity than randomly selected sites without microdamage (relative risk 2.39, 95% confidence interval of relative risk: 2.09-2.73), indicating a spatial association between resorption cavities and microdamage at the local level. Individual microdamage sites were 48,700 (40,100; 62,700) μm(3) in size (median, 25th and 75th percentiles). That microdamage was associated with resorption cavities when measured at the whole specimen level as well as at the local level provides strong evidence that resorption cavities play a role in mechanical failure processes of cancellous bone and therefore have the potential to influence resistance to clinical fracture.

Total motion generated in the unstable thoracolumbar spine during management of the typical trauma patient: a comparison of methods in a cadaver model

OBJECT

The proper prehospital and inpatient management of patients with unstable spinal injuries is critical for prevention of secondary neurological compromise. The authors sought to analyze the amount of motion generated in the unstable thoracolumbar spine during various maneuvers and transfers that a trauma patient would typically be subjected to prior to definitive fixation.

METHODS

Five fresh cadavers with surgically created unstable L-1 burst fractures were tested. The amount of angular motion between the T-12 and L-2 vertebral segments was measured using a 3D electromagnetic motion analysis device. A complete sequence of maneuvers and transfers was then performed that a patient would be expected to go through from the time of injury until surgical fixation. These maneuvers and transfers included spine board placement and removal, bed transfers, lateral therapy, and turning the patient prone onto the operating table. During each of these, the authors performed what they believed to be the most commonly used versus the best techniques for preventing undesirable motion at the injury level.

RESULTS

When placing a spine board there was more motion in all 3 planes with the log-roll technique, and this difference reached statistical significance for axial rotation (p = 0.018) and lateral bending (p = 0.003). Using logrolling for spine board removal resulted in increased motion again, and this was statistically significant for flexion-extension (p = 0.014). During the bed transfer and lateral therapy, the log-roll technique resulted in more motion in all 3 planes (p ≤ 0.05). When turning the cadavers prone for surgery there was statistically more angular motion in each plane for manually turning the patient versus the Jackson table turn (p ≤ 0.01). The total motion was decreased by almost 50% in each plane when using an alternative to the log-roll techniques during the complete sequence (p ≤ 0.007).

CONCLUSIONS

Although it is unknown how much motion in the unstable spine is necessary to cause secondary neurological injury, the accepted tenet is to minimize motion as much as possible. This study has demonstrated the angular motion incurred by the unstable thoracolumbar spine as experienced by the typical trauma patient from the field to positioning in the operating room using the best and most commonly used techniques. As previously reported, using the log-roll technique consistently results in unwanted motion at the injured spinal segment.

A biomechanical assessment of floor and overhead lifts using one or two caregivers for patient transfers

This study investigated the differences in peak external hand forces and external moments generated at the L5/S1 joint of the low back due to maneuvering loaded floor-based and overhead-mounted patient lifting devices using one and two caregivers. Hand forces and external moments at the L5/S1 joint were estimated from ground reaction forces and motion capture data. Caregivers gave ratings of perceived exertion as well as their opinions regarding overhead vs. floor lifts. Use of overhead lifts resulted in significantly lower back loads than floor lifts. Two caregivers working together with a floor lift did not reduce loads on the primary caregiver compared to the single-caregiver case. In contrast, two-caregiver operation of an overhead lift did result in reduced loads compared to the single-caregiver case. Therefore, overhead lifts should be used whenever possible to reduce the risk of back injury to caregivers. The use of two caregivers does not compensate for the poorer performance of floor lifts.

[Spinal injury: multidetector computed tomography features and mechanism]

As one of the severe injuries, spinal injury is common in major blunt trauma and a spinal cord injury can make the patient be disabled or life-threatened with poor long-term physical and psychological consequences. The treatment of spinal injuries is a significant proportion of all the workload of trauma management based on the neurologic defect, spinal column instability, and the compression of spinal cord. Multidetector computed tomography (MDCT) is the better examination than conventional radiography in depicting the type of injuries, spinal column instability, spinal canal narrowing degree and neurologic defect, and can be performed alone in patients sustaining severe trauma. The purpose of this review is to evaluate the MDCT features of this types of injuries based on the mechanism.

A cable-driven locomotor training system for restoration of gait in human SCI

A novel cable-driven robotic locomotor training system was developed to provide compliant assistance/resistance forces to the legs during treadmill training in patients with incomplete spinal cord injury (SCI). Eleven subjects with incomplete SCI were recruited to participate in two experiments to test the feasibility of the robotic gait training system. Specifically, 10 subjects participated in one experimental session to test the characteristics of the robotic gait training system and one subject participated in repeated testing sessions over 8 weeks with the robotic device to test improvements in locomotor function. Limb kinematics were recorded in one experiment to evaluate the system characteristics of the cable-driven locomotor trainer and the overground gait speed and 6 min walking distance were evaluated at pre, 4 and 8 weeks post treadmill training of a single subject as well. The results indicated that the cable driven robotic gait training system improved the kinematic performance of the leg during treadmill walking and had no significant impact on the variability of lower leg trajectory, suggesting a high backdrivability of the cable system. In addition, results from a patient with incomplete SCI indicated that prolonged robotic gait training using the cable robot improved overground gait speed. Results from this study suggested that a cable driven robotic gait training system is effective in improving leg kinematic performance, yet allows variability of gait kinematics. Thus, it seems feasible to improve the locomotor function in human SCI using this cable driven robotic system, warranting testing with a larger group of patients.

Evaluation of dynamic formation of cervical spine column based on functional radiological studies in patients after cervical spine injury

The purpose of this study was to evaluate cervical spine function, based on our own functional method of roentgenometric analysis in patients who suffered from cervical spine sprain injury. Study involved 72 patients who suffered from cervical spine whiplash injury. Conventional plain radiographs in all patients included three lateral views: maximum flexion, neutral (resting) and maximum extension. All views allowed roentgenometric evaluation of ligament instability of the lower cervical spine C5-C7 according to the White and Panjabi criteria. Furthermore, based on literature analysis and their own clinical observations, the authors proposed new classification of dynamic formation of cervical spine column. The dynamic formation of cervical column is evaluated based on pathomechanical chain of being between normal and unstable. Authors' own evaluation system in flexion views can be useful in diagnosis and treatment of this type of injury.

Influence of whiplash injury on cervical spine stability

The aim of this study was to define the influence of whiplash injury on cervical spine stability. The study involved 72 patients who had suffered from sprain injury to cervical spine of 0⁰-III⁰ according to QTF. To verify the results the authors examined the control group whose representatives have never suffered from any cervical spine injury and met all the exclusion criteria. Conventional plain radiographs in both groups showed three lateral views: maximum flexion, neutral (resting) position and maximum extension view. The results of image studies were subjected to roentgenometric analysis to find mechanical symptoms of instability according to radiological criteria: AADI, anterior translation and regional angulation. The authors demonstrated that there was no influence of whiplash injury on mechanical stability of cervical spine measured on radiograms in static-functional lateral views.

[Accident analysis and biomechanics: relevance of technical reports for the medical assessment of spinal injuries]

The number of claims linked to whiplash injuries is steadily increasing in most European countries. After minor accidents the question often arises as to whether the occupant could really have been injured. The technical expert may calculate the biomechanical stress imposed on the occupants by the impact from the evidence gathered after the accident. Based on this data the medical expert is able to judge whether this stress was sufficient to produce the injury claimed. The threshold of biomechanical loading necessary for spinal injuries will be deduced from a technical perspective. With the help of examples, the steps required to preserve evidence will be explained.

Kinematic response of the spine during simulated aircraft ejections

INTRODUCTION

Military aviators are susceptible to spinal injuries during high-speed ejection scenarios. These injuries commonly arise as a result of strains induced by extreme flexion or compression of the spinal column. This study characterizes the vertebral motion of two postmortem human surrogates (PMHS) during a simulated catapult phase of ejection on a horizontal decelerator sled.

METHODS

During testing, the PMHS were restrained supinely to a mock ejection seat and subjected to a horizontal deceleration profile directed along the local z-axis. Two midsized males (175.3 cm, 77.1 kg; 185.4 cm, 72.6 kg) were tested. High-rate motion capture equipment was used to measure the three-dimensional displacement of the head, vertebrae, and pelvis during the ejection event.

RESULTS

The two PMHS showed generally similar kinematic motion. Head injury criterion (HIC) results were well below injury threshold levels for both specimens. The specimens both showed compression of the spine, with a reduction in length of 23.9 mm and 45.7 mm. Post-test autopsies revealed fractures in the C5, T1, and L1 vertebrae.

DISCUSSION

This paper provides an analysis of spinal motion during an aircraft ejection.The injuries observed in the test subjects were consistent with those seen in epidemiological studies. Future studies should examine the effects of gender, muscle tensing, out-of-position (of head from neutral position) occupants, and external forces (e.g., windblast) on spinal kinematics during aircraft ejection.

High cycle fatigue behaviour of functional spinal units

Vibrations have been shown to be an important risk factor for spinal pathologies. The underlying mechanisms are poorly understood and in vivo data scarce and difficult to obtain. Consequently numerical models are used to estimate spinal loading; requiring fatigue strength information, which was obtained in this study for spinal specimens from young and old male donors of working age in vitro. Bone mineral density (BMD) and endplate area were determined using CT scans. Three groups were investigated: young specimens in neutral posture, young in flexed posture, and old in neutral posture. The loading consisted of 300,000 sinusoidal compression cycles of 2 kN, inducing a nucleus pressure peek of approximately 1.4 MPa. No failure of the young specimens in neutral posture was observed, but four specimens from older donors with low BMD failed. The product between endplate area and BMD was shown to be useful to predict fatigue strength for old donors and should therefore be considered with regard to whole body vibration injuries. In flexed posture, two specimens from young donors failed. One failure can be attributed to low BMD following the trend for the old specimens; the other failure could not be explained, leaving the influence of flexion yet unclear.

Rehabilitation of the spine following sports injury

The spine plays an essential role in the contribution toward athletic performance. As the central pillar of the body, the structures of the spine are susceptible to injury related with sports participation. This article identifies many of the most commonly seen sports-related injuries to the spine, and discusses practical rehabilitative interventions to manage such injuries. Anatomic considerations, biomechanical movements, and tissue properties are explained to better understand the clinical expectations associated with each of the injuries described.

Rear seat occupant safety: an investigation of a progressive force-limiting, pretensioning 3-point belt system using adult PMHS in frontal sled tests

Rear seat adult occupant protection is receiving increased attention from the automotive safety community. Recent anthropomorphic test device (ATD) studies have suggested that it may be possible to improve kinematics and reduce injuries to rear seat occupants in frontal collisions by incorporating shoulder-belt force-limiting and pretensioning (FL+PT) technologies into rear seat 3-point belt restraints. This study seeks to further investigate the feasibility and potential kinematic benefits of a FL+PT rear seat, 3-point belt restraint system in a series of 48 kmh frontal impact sled tests (20 g, 80 ms sled acceleration pulse) performed with post mortem human surrogates (PMHS). Three PMHS were tested with a 3-point belt restraint with a progressive (two-stage) force limiting and pretensioing retractor in a sled buck representing the rear seat occupant environment of a 2004 mid-sized sedan. Instrumentation included belt tension load cells, accelerometers on the head and at multiple locations on the spine, and chestbands to measure the chest deformation contours in the transverse plane. The kinematics of the subjects were quantified using off-board, high-speed video. The results of these tests were then compared to matched PMHS tests, published in 2008, performed in the same environment with a standard (not-force limited, not pretensioning) 3-point belt restraint. The FL+PT restraint system resulted in significant (p<0.05) decreases in peak shoulder belt tension (average +/- standard deviation: 4.4 +/- 0.13 kN with the FL+PT belt, 7.8 +/- 0. 6 kN with the standard belt) and 3 ms-resultant, mid-spine acceleration (FL+PT: 34 +/- 3.8 g; standard belt: 44 +/- 1.4 g). The FL+PT tests also produced more forward torso rotation caused by decreased forward excursion of the pelvis and increased payout out of the shoulder belt by the force-limiter. These results support the previous ATD studies that suggest that it may be possible to improve the kinematics of rear seat occupants in this type of collision using a 3-point belt system with a shoulder belt retractor equipped with a two-stage force-limiter and pretensioner.

Airway management for cervical spine injury

In this review, important factors related to initial management, diagnosis, airway, and anesthetic management of patients with cervical spine injury (CSI) are discussed. Early diagnostic and clinical evaluation is important in excluding CSI. In-line stabilization reduces movement of the cervical spine. Tracheal intubation under fiberscopic control, offers safety, and comfort to the patient. However, in cases of severe deterioration of vital functions, intubation must be performed without any delay at the site of the accident or in the emergency room. Early airway management and maintenance of spinal immobilization are more important factors in limiting the risk of secondary neurological injury than any particular technique. The current opinion is that oral intubation after intravenous induction of anesthesia and muscle relaxation along with in-line stabilization is the safest and quickest way to achieve intubation in a patient with suspected CSI.

Impact of injury on changes in biomechanical loads in human lumbar spine

Implementation of new spine stabilisation systems should be preceded by the analysis of the behaviour of healthy and damaged spine under laboratory conditions. Research was performed on two-part and three-part segments without damage and with disc damage in the two-part segment, and with a wedge cut in the vertebra in the three-part segment. In the two-part segment, a relative power necessary for inducing extension-compression in the damaged segment is twice as high as in the damaged three-part segment. In the damaged two-part segment, the motion in the sagittal plane needs a relative power being more than twice as high as in the damaged three-part segment. Yet absolute average values of powers examined in the two-part and three-part segment systems in the undamaged spine for all types of motion were similar, with slight advantage of the two-part segment system. Basic two-part segment of the spine motion system is its most stable functional part.

[Treatment of post-traumatic instability of the cervical spine--30 years experience]

BACKGROUND

Assessment of the stability of the cervical spine following an injury is an important part of the diagnostic work-up. It is not always easy as the mechanism of injury does not always determine the degree of spinal stability. An actual instability is often confused with increased compensatory instability that is still within physiological limits, i. e. excessive mobility of the segment positioned above the part that has been immobilised as a result of trauma or vertebral block. Spinal injuries with instability are usually an indication for surgery. On the basis of 30 years' experience, the author presents indications for anterior approach surgery, based on the mechanism of injury and the patient's neurological status following an injury to the cervical spine.

MATERIAL AND METHODS

A total of 1,225 patients have been operated on. Indications are defined for surgery using rod or plate implants and compression plates. Radiographic and neurological outcome data are presented for 1138 who had been followed up for at least 6 months.

RESULTS

A good radiographic outcome was obtained in a total of 78% patients, including 84% of the recipients of rod implants and 65% of the recipients of plate implants. Neurological improvement was seen in 68% of patients with neurological symptoms, including substantial improvements in 26% of the patients.

CONCLUSIONS

1. Assessment of spinal stability is an important element of diagnostic work-up. 2. It is essential to distinguish actual instability requiring surgery from a compensatory increase in mobility of the segment lying above the immobilised segment of the spine. 3. An anterior approach procedure, apart from stabilising the spine, serves to decompress the spinal cord and offers a chance of neurological and functional improvement.

Effect of various electric field strengths and current durations on stunning and spinal injuries of Atlantic herring

The aim of this study was to evaluate the effect of electric field strength and current duration on wild-caught Atlantic herring Clupea harengus stunned with sinusoidal 50-Hz AC in seawater. The fish were exposed to electric field strengths ranging from 16 to 142 V/m and current durations from 1 to 12 s. We recorded the elapsed times between the point at which each fish became unconscious and the points at which it resumed normal behavioral functions. We also investigated injuries such as broken spinal columns and hematomas after the fish were filleted. The threshold electric field strength required to stun all of the fish to unconsciousness was 33 V/m for 1 s. The duration of the unconscious condition increased as both electric field strength and current duration increased. Of a total of 260 Atlantic herring, 60% had broken spinal columns. The proportion of fish with fractured spines was independent of field strength and duration, but the number of fractures per fish increased with field strength. We conclude that electrical stunning would promote the welfare of Atlantic herring that are landed alive but negatively affect fillet quality owing to hematomas associated with the fractures.

A method to provide a more efficient and reliable measure of self-report physical work capacity for patients with spinal pain

Self-report measures of functional ability are commonly used in occupational rehabilitation to measure the current status of an individual and his or her progress in response to intervention. Most of these measures have been developed using classical test theory that does not provide calibration of the items. Methods of test development that originated in the field of Education have been applied recently to healthcare measures, providing item calibration and allowing proportional evaluation of total scores. The purpose of this article is to demonstrate the application of these methods in the revision of an existing self-report measure. The potential value of these methods to improve established measures is demonstrated.