Smart garment to help children improve posture.

Many of the aches and pains of adults are the result not of injuries, but of the long-term effects of distortions in posture or alignment. Postural kyphosis in adolescence may be one of the effects of poor standing and sitting habits. Kyphosis is an excessive rounding of the upper spine. A smart garment that can monitor and provide vibration feedback to children has been developed to investigate an alternative treatment possibility. Laboratory tests verified that the accuracy of the system was +/-2 degrees within the full 180 degrees range. A clinical trial has been conducted and it showed that the system can aid subjects to improve by 20% the proportion of time in a more balanced posture. The long term effect is still under investigation.

Smart orthosis for the treatment of adolescent idiopathic scoliosis.

There is considerable controversy regarding the effectiveness of orthotic treatment for patients with adolescent idiopathic scoliosis. Most researchers believe that, to be effective, the orthosis must be worn as prescribed for both compliance and tightness. Compliance is the time the brace is worn relative to the prescribed time. A battery-powered microcomputer system was developed to monitor and maintain the loads exerted by orthoses used to treat children with spinal deformities during daily living. This system not only records how well and for how much time the brace has been used, but also helps patients to ensure that the brace is being worn at the prescribed tightness. Laboratory tests were performed, and five patients used the system for four weeks. The patients reported that the system helped them to wear the orthoses correctly and comfortably. The time that the patients wore the orthoses at the prescribed tightness level increased from 53 +/- 9% during the monitoring period (first 2 weeks) to 68 +/- 14% during the automatic adjustment period (last 2 weeks).

Correlation between quantity and quality of orthosis wear and treatment outcomes in adolescent idiopathic scoliosis.

Orthotic treatment is the most commonly used non-surgical treatment method for adolescent idiopathic scoliosis (AIS). This study determined whether treatment outcome correlates with how often and how well children with AIS wear their orthoses. Eighteen (18) subjects (3M, 15F) who were diagnosed with idiopathic scoliosis and had worn their orthoses from 6 months up to 1 year participated in this study. All subjects were prescribed Boston braces to be worn full time (23 hrs/day). Twelve (12) subjects who completed their brace treatment were included in the data analysis. Three (3) treatment outcomes were classified as improvement, no change and deterioration. The quality of the brace wear was assessed by how often the brace was worn with zero force, below 80%, between 80 to 120%, and above 120% of the load level prescribed in the clinic. The quantity of brace wear was determined by how many hours per day they wore their brace. Subjects who wear their braces tighter and for more hours per day seem to have better outcomes.

Bluetooth wireless database for scoliosis clinics.

A database system with Bluetooth wireless connectivity has been developed so that scoliosis clinics can be run more efficiently and data can be mined for research studies without significant increases in equipment cost. The wireless database system consists of a Bluetooth-enabled laptop or PC and a Bluetooth-enabled handheld personal data assistant (PDA). Each patient has a profile in the database, which has all of his or her clinical history. Immediately prior to the examination, the orthopaedic surgeon selects a patient's profile from the database and uploads that data to the PDA over a Bluetooth wireless connection. The surgeon can view the entire clinical history of the patient while in the examination room and, at the same time, enter in any new measurements and comments from the current examination. After seeing the patient, the surgeon synchronises the newly entered information with the database wirelessly and prints a record for the chart. This combination of the database and the PDA both improves efficiency and accuracy and can save significant time, as there is less duplication of work, and no dictation is required. The equipment required to implement this solution is a Bluetooth-enabled PDA and a Bluetooth wireless transceiver for the PC or laptop.

Instrumented rod rotator system for spinal surgery.

An electronically instrumented rod rotator has been developed to monitor forces and moments applied by surgeons during the derotation manoeuver to correct spinal curvature. This instrumented rod rotator consisted of an inclinometer and two pairs of strain gauges, with all the support circuitry. The strain gauge and the inclinometer data were sampled with a data-acquisition system, and the results were displayed in real time. The device was calibrated in the laboratory and used on seven subjects. The precision of the load measurement of this device was +/- 5 N in the range of 5-65N. The distance between the middle of the rod rotator handle to the rod position was 0.21 m. The maximum loads applied by the surgeon during seven surgeries were from 22 to 57N, with a torque (force x distance) from 4.6 to 12 Nm.

Using three-dimensional difference maps to assess changes in scoliotic deformities.

The three-dimensional nature of scoliosis, coupled with changes due to natural history or treatment, is often difficult to quantify and visualise. A difference map was developed to compare the sequential surface topography of subjects over their treatment period. Three-dimensional surface maps representing patients' trunk surfaces were captured with a laser scanner. Patient surface maps from two clinic visits were matched using a manual best-fit technique that accounted for growth and positioning. The surfaces were subtracted, generating a colour-coded three-dimensional difference map displaying the surface changes. The difference maps were compared with known clinical measures, indicating good agreement (78% specific) with the clinical parameters in detecting change. Full agreement or agreement with the clinical parameters occurred in the surgical, brace and no treatment groups: 76%, 80% and 85%, respectively. A difference index (average of the absolute value of differences on a point-by-point basis) was calculated from the difference map, enabling quantification of change. The difference index, with zero being a perfect match, averaged 5 +/- 1 for repeated measures 7 +/- 2 for subjects deemed to have no change, 9 +/- 2 for subjects with slight change, and 14 +/- 2 for subjects with significant change. The difference map showed the extent and location of changes and is a useful tool for assessing surface topography changes.

The daily force pattern of spinal orthoses in subjects with adolescent idiopathic scoliosis.

The efficacy of orthotic treatment for children with abnormal spinal curvature has been hampered by the lack of comprehensive information about wear characteristics. A battery-powered microcomputer system was developed to monitor loads exerted by orthoses used to treat children with spinal deformities during daily living. The system not only records how well the orthosis has been used, but also helps to ensure that the orthosis is being worn as prescribed. Data acquisition is controlled by a microcontroller and can be programmed to have sample intervals ranging from 1 second to 1 hour. Low power control circuitry is designed so that the system can be operated by a battery. In a preliminary study, 16 subjects (3M, 13F) used this system from 1 to 16 days (9.3 +/- 5.0) with the prescribed hours between 16 to 23 hours (22.3 +/- 1.3). This study demonstrated the feasibility of the approach, and that this device may increase the understanding of orthotic mechanics, and may help patients to wear their orthoses in a better way.

Evaluation of a laser scanner for surface topography.

A Minolta VIVID 700 portable non-contact 3D laser scanner was evaluated on 15 subjects with idiopathic scoliosis. The 3D map was compared to two structured light pattern (lines and dots) techniques to determine the reliability, ease of use, speed, and quality. The parameters used for the clinical assessment of scoliosis were measured twice for the Minolta and light projection systems. The edges of the image and areas where occlusion typically occur were examined. The absolute distance in calculated depth between adjacent points was examined to determine errors. The Minolta system and the dot pattern produced regular grids of points. The light projection pattern produced an irregular grid, with more resolution along the video line and less resolution between projected lines, resulted in a somewhat jagged appearance of the surface map. The Minolta system was less sensitive to edge effects, occlusion, and sharp transitions of depth. The comparison of clinical parameters showed good results between repetitions but moderate results between techniques.

Image coding technique for 3-D back reconstruction.

This work investigated the use of coded-line patterns to improve image correspondence and 3D reconstruction. The objective was to define an optimum structured light pattern to facilitate the construction of topographic maps of the trunks of scoliosis patients. The system consisted of stereo CCD television cameras, a slide projector to create the coded-line pattern and a computer with video acquisition card. The optimum pattern in terms of generating correct results with minimum computing time was a line pattern consisting of 6 groupings of 3-level grey lines. This chosen pattern was investigated using known 3D objects to determine the effectiveness, resolution and computational time to correlate stereo images. The selected structured light pattern consisted of a repeated pattern of white (W), grey (G) and black (B) lines. Each line was 4mm wide on the back surface. The pattern consisted of 6 groups of 3 lines, WBG WGB GWB GBW BGW BWG. Using known 3D models of a section of a cylinder, a plate with steps and a ramp-like object; the coded line system was tested under typical clinical lighting conditions. For the 3D test objects, errors in correspondence occurred in 2-4 % of stereo pixels. The processing time varied from 10-12 minutes. The 3D resolution obtained was 4mm.

Intra-operative measurement of vertebral bone strength.

A significant complication of surgical correction of the deformed spine is pull out of the vertebral hooks or screws. This complication can be partly attributed to poor bone stock. Currently, there are few methods available for surgeons to assess the mechanical strength and stiffness of the vertebra, and even fewer methods that provide in-vivo measurements. An "upbiter" is often used to form a seat in the lamina for the hook. A typical upbiter was modified and instrumented with strain gauges to investigate the feasibility of determining the forces and displacements needed to cut through laminar bone during surgical procedures. The calibration showed that the system was repeatable and could highly correlated with applied force (R2=0.98) and displacement (R2=0.99) with resolutions of 0.72 N and 0.40 mm respectively. This system was tested on three females, on lamina ranging from T4 to T12 regions. The average maximum force for bone failure was at 470+/-128N.

Computer modelling of hooks for use as intra-operative force sensors.

There are a number of forces applied during scoliosis surgery, the magnitude and direction of which remains unknown. There is little literature concerning the in vivo distribution of forces along the spine. Computer modelling (ANSYS) was used to investigate the possibility of using an instrumented hook to intra-operatively measure the antero-posterior and distraction/compression forces applied by the surgeon during corrective scoliosis surgery. Three hook designs were evaluated based on specific design criteria. ANSYS provided the preliminary analysis to determine the strain distribution in these hooks. One design, the "membrane" design, was selected and a prototype was manufactured. Preliminary tests demonstrate that this prototype will be able to differentiate between the four major forces applied during the surgical correction.

Is the Boston brace mechanically effective in AIS?

The application of three-point loading is thought to be the essential basis for effective bracing of adolescent idiopathic scoliosis. Care is taken to ensure that active pressure pad is located to provide maximum support to the apex of the scoliosis while minimizing its lordosising effect. Paradoxically, while cited as an essential factor in the design of braces, there is no consensus as to the importance of such loading to the clinical effectiveness of braces. It may be that braces are effective but that they are effective for reasons unrelated to mechanics. There are few studies that link brace mechanics and change in spinal alignment. Optimal bracing for AIS requires a much better understanding of the role of the mechanical support of braces used to treat AIS. Sixteen subjects, 3 males and 13 females, were participated to this study to determine the correlation between quantity and quality of brace wear and treatment outcomes in AIS. This study showed that the target force levels set for the active pad in braces prescribed for the treatment of AIS vary considerably and that brace applies the desired load 25% of the prescribed time.

Trunk distortion in adolescent idiopathic scoliosis.

Trunk images of children with scoliosis were examined to determine features that contribute to the impression of trunk distortion. Twenty subjects with spinal deformity ranging from none to severe were photographed in a relaxed standing position. Seven blinded evaluators subjectively scored their impressions of the trunk appearance, shoulder-height difference, shoulder-angle asymmetry, decompensation, scapula asymmetry, waist crease, waist asymmetry, and pelvic asymmetry. Regression analysis was used with the latter seven features to predict overall impression. The seven measures of the deformity predicted 85% of the overall impression of trunk distortion; scapular asymmetry was the best predictor. Trunk deformity is the most obvious effect of scoliosis to the patients. Objective approaches to the assessment of this important but difficult-to-quantify aspect of idiopathic scoliosis are available and should be used to evaluate treatment outcomes.

The nature and distribution of the innervation of human supraspinal and interspinal ligaments.

STUDY DESIGN: To use fresh, human supraspinal and interspinal ligaments and document their innervation. OBJECTIVES: To characterize the innervation of the human supraspinal and interspinal ligaments. SUMMARY OF BACKGROUND DATA: The nature and distribution of the innervation of spinal ligaments remains unknown. METHODS: Sections of spinal ligaments were labeled with a fluorescent antibody against neurofilament proteins and observed with a confocal microscope. RESULTS: The ligaments were found to be well innervated. Innervation was equally distributed along the ligament, symmetrically distributed between left and right sides, and more densely distributed in the periphery. Pacinian corpuscles were scattered randomly, close to blood vessels, whereas Ruffini corpuscles were in the periphery, close to the collagen bundles. CONCLUSIONS: Human supraspinal and interspinal ligaments are well innervated. This innervation might form the basis of neurologic feedback mechanisms for the protection and stability of the spine. These mechanisms might also be important in the development of diseases such as scoliosis.

Quantitative morphology of the lateral ligaments of the spine. Assessment of their importance in maintaining lateral stability.

STUDY DESIGN: This study used human cadaveric material to examine the three-dimensional morphology and biomechanics of the superior and lateral costotransverse ligaments and the intertransverse ligament of the spine. OBJECTIVES: To provide descriptive and quantitative data on the morphology of the lateral ligaments of the spine and to assess their importance in maintaining lateral stability, especially regarding the pathogenesis of idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: Ligaments have been reported as being able to stabilize the spine by mechanical constraint and by neurologic feed-back. Midline spinal ligaments have been well studied but do not appear to be effective in maintaining lateral stability because of their sites of attachment. Lateral ligaments of the spine have not been adequately documented in the literature. METHODS: The morphology, sites of attachment, and dimensions of the superior costotransverse ligament, lateral costotransverse ligament, and intertransverse ligament from thoracic level 7 to thoracic level 10 were determined on 32 human cadavers. RESULTS: The intertransverse ligament was found not to be a true ligament. The lateral costotransverse ligament was a true ligament but did not have the characteristics appropriate for involvement in lateral stability. The superior costotransverse ligament also was a true ligament and had all of the characteristics appropriate for involvement in the active lateral balancing of the spine. CONCLUSIONS: In contrast to the midline ligaments of the spine, the superior costotransverse ligament perhaps is the most important ligament for active lateral balancing of the spine and warrants further study, particularly regarding the development of idiopathic scoliosis.

Vibratory response in adolescents who have idiopathic scoliosis.

The PVD Bio-Thesiometer was tested as a tool for measuring vibratory thresholds and for detecting possible differences in these thresholds between adolescents who have idiopathic scoliosis and those who do not. It was found to be limited by low reliability and large errors in measurement, with the metatarsophalangeal joint being the only reliable site for measurement. The vibratory thresholds at this site were significantly higher in the fourteen subjects who had scoliosis than in the twenty-two control subjects. No significant asymmetry in vibratory thresholds was found between the concave and convex or the right and left sides in either the scoliotic or the control group. Because there was no significant difference between the readings from the concave and convex sides, it is unlikely that a lesion of the posterior column is responsible for idiopathic scoliosis. If there is a difference, then the PVD Bio-Thesiometer is not sufficiently reliable to detect it.

End-cap for the biomechanical testing of spinal segments.

Precise mechanical loading is essential in the in vitro evaluation of spinal fixation instrumentation, but the control of experimental variables is difficult because of variations in specimen morphology, size and end conditions, and gross specimen flexibility. This paper describes an end-cap which is simple in design, time efficient in its attachment to the spine and which provides precise positioning and rigid control of the end fixation points, resulting in excellent experimental control. It is easily adapted to human or animal specimens and provides a reliable load application unit, which permits specific physiological end conditions to be applied.

A transducer for measuring motion within a vertebra.

Accurate in vitro evaluation of the efficacy of spinal instrumentation devices requires specialized equipment. A displacement transducer that directly measures motion at the fracture site has been designed. Data are processed on-line by computer. Tests using an earlier photographic technique simultaneously with the transducer show the new method to be more accurate and reliable and the results more readily available. Application of the transducer for monitoring fracture creation and end-cap purchase is also shown.

Vertebral end-plate failure in porcine and bovine models of spinal fracture instrumentation.

The use of mature porcine and immature bovine spines as models for the assessment of spinal fracture instrumentation is commonplace. By comparing the load-displacement characteristics of these spine segments and observing the fracture type, this study investigated the tendency of immature bovine spines to fail prematurely at the vertebral physis, disrupting biomechanical evaluation of spinal fracture fixation devices. Load to failure of the spines was determined using the Instron Universal Testing Machine and a specially designed endcap. In axial compression, the 10-16-week-old calf spines failed at 12,845 +/- 1,466 N, compared with mature pig spines at 17,300 +/- 5,170 N (p less than 0.05). Axial compression with flexion caused consistent failure through an end-plate in both species: 995 +/- 156 N for the calf spines and 2,025 +/- 575 N for the porcine spines (p less than 0.005). It was concluded that the tendency for immature bovine spines to fail more readily at the cartilaginous end-plate makes the calf spine a less desirable model.