Spine-rib rotation differences at the apex in preoperative patients with adolescent idiopathic scoliosis: evaluation of a three-level ultrasound method

This paper evaluates a new real-time ultrasound method to assess the difference between axial spinal (laminal) rotation and rib rotation at the apex of the scoliosis curve. An Aloka SSD 500 portable ultrasound machine with a veterinary long (172mm) 3.5 MHz linear array transducer was used to assess the reproducibility of the method in 13 preoperative patients with AIS. With the subject in a prone position and her head supported, readings of laminal and rib rotation were made directly on the back at 18 and 12 levels respectively The subject was repositioned after walking around the room and a second set of spinal and rib rotations obtained (repeats). All the readings were made by one observer (ASK). After plotting on graphs three levels of maximal difference between spine rotation and rib rotation about the apex were chosen visually by one observer (RGB) for which the mean apical spine-minus-rib rotation difference (SRRD) was calculated for each repeat. Findings for apical SRRDs. The mean apical SRRDs for the two repeats are 7.1 degrees and 6.9 degrees (range 2-18 degrees) with coefficients of variation of 49% and 62% respectively. Reproducibility. Graphic representation of spinal and rib rotation by 12 levels shows a fairly good agreement between repeats for most subjects. Spinal rotation is always greater than rib rotation. A paired t-test for the mean apical SRRD of the repeats shows no significant difference. Linear regression analysis of the mean apical SRRD repeats correlate significantly (r=0.70, P=0.008) with a residual mean square of 6.9 degrees (rms = 2.6 degrees). The technical error of the measurement (TEM) is 2.3 degrees and coefficient of reliability (R) 0.66. Conclusions. Real-time ultrasound can assess the difference between spinal and rib rotation about the apex of the scoliosis curve without the altered position detectably affecting the findings. The error (2-3 degrees) is high relative the mean apical SRRD (6-7 degrees). The apical SRRD findings have relevance to the pathogenesis of AIS.

Anterior universal spine system for adolescent idiopathic scoliosis: a follow-up study using scoliometer, real-time ultrasound and radiographs

Nine patients with AIS treated surgically with anterior USS instrumentation were examined by several methods pre-operatively and at each of 8 weeks, 1 year and 2 years after surgery (mean age 14.6 years, girls 7, boys 2, thoracolumbar 7, lumbar 1, thoracic 1, left 7, right 2). The methods used were (1) Scoliometer to measure angle of trunk inclinations (ATIs) in the standing forward bending position at each of 10 levels and converted to 18 levels by a computer program, (2) real-time ultrasound in the prone position of laminal rotations at each of 1 8 levels from TI-SI, and (3) anteroposterior radiographs in the standing erect position measured for each of Cobb angle, segmental vertebral rotation (Perdriolle) and segmental vertebral translation from the Ti-Si line (horizontal translation of each vertebral centroid from the T1-S1 line). The findings were plotted graphically and segmentally for each of Scoliometer ATJs, ultrasound laminal rotations, and radiographic vertebral rotations and translations. Findings. Graphical representation of the data shows that the improvement brought about by surgery is most clearly and consistently evident for segmental vertebral translation. The statistical analysis shows that the radiological parameters (Cobb angle, apical vertebral rotation and apical vertebral translation) and ultrasound spinal (laminal) rotation do not change detectably in follow-up. The Scoliometer ATI findings show an increase from 4 degrees (at 8 weeks) to 7 degrees (at 2 years) which is statistically significant. The evidence from this small sample of patients is consistent with the view that the compared with posterior USS, anterior USS surgery for AIS results in (1) similar initial rib hump correction, and (2) less rib hump reassertion during follow-up. More data are needed to evaluate these views.

The early detection of adolescent idiopathic scoliosis in three positions using the scoliometer and real-time ultrasound: should the prone position also be used?

The standing forward bending position is in general use for the early detection of adolescent idiopathic scoliosis. It also reveals humps caused by leg-length inequality and for this reason some workers have advocated using the sitting forward bending position. Most recently the prone position has been evaluated and even recommended. The introduction of B-mode and subsequently real-time ultrasound to measure rib rotation and spinal rotation has involved using the prone position. The numerical description of back humps in scientific studies requires measurements at several levels on the back from T1-S1. This paper utilizes 30 subjects referred by school screening for scoliosis from whom 10-level Scoliometer Angle of Trunk Inclinations (ATIs) were obtained twice in each of three positions--standing forward bending, sitting forward bending and prone. The ATIs were converted to 18 levels and (1) analysed for reproducibility, (2) compared in the three positions, and (3) compared with real-time ultrasound data of rib rotation obtained in the prone position. Several statistical methods are used. The reproducibility is best in the sitting and prone positions. While the prone position produces lower ATI readings, R squared values are significantly higher and Residual Mean Square (RMS) values significantly lower than those for each of the standing and sitting forward bending positions. Though the prone position has clear advantages, it is not advocated in clinical practice for various reasons. More research is needed. The evidence supports the view that the sitting forward bending position has advantages for the early detection of adolescent idiopathic scoliosis.

Etiologic theories of idiopathic scoliosis: neurodevelopmental concepts to be evaluated

There is increasing interest in the concept that neuromuscular mechanisms and the central nervous system (CNS) are somehow involved in the etiology and pathogenesis of idiopathic scoliosis (IS). Yet in the extensive neuroscience research of idiopathic scoliosis certain neurodevelopmental concepts have been neglected. These include: (1) a CNS body schema for posture and movement control generated during development and growth by establishing a long-lasting memory; (2) pruning of cortical synapses at puberty; and (3) neuromorphic engineering. Memory of developing posture and movement might be established in neurons of the CNS body schema in the form of novel proteins; these could be coded by modified genes obtained by the recombination (crossing over) of DNA in a similar way to that in the production of immunological antibodies and during meiosis. These concepts need evaluation in relation to (1) the etiopathogenesis of IS and (2) a possible new treatment approach to idiopathic scoliosis involving a neuromorphic device to control the output for muscle stimulators that are inserted and driven with telemetry.

Etiologic theories of idiopathic scoliosis: the apical spinal deformity--relevance to surgical practice

The current successful management of idiopathic scoliosis is an orthopaedic and not a paediatric responsibility. Hence the immediate aim of etiologic research is to improve surgical treatments based on a better understanding of the causation of the deformity. This focuses attention on the pathomechanisms of the spinal and ribcage deformities. The mechanisms of spinal deformity about the apex are unresolved but may be caused by forces created in the anterior spinal column. Some current theories with practical application involve (1) front-back spinal growth mechanisms, (2) rib growth asymmetry and (3) muscles.

CONCLUSIONS

The application of theory to surgical practice is advanced for concepts of front-back spinal growth asymmetry but rib hump reassertion occurs after surgery and these concepts ignore the ribcage as a possible factor in scoliosis pathogenesis. A theory of ribcage asymmetry involving concave rib overgrowth is beginning to be evaluated surgically. After surgery for IIS and AIS reassertion of the deformity has been shown to involve preoperative spinal and concave rib factors; the larger the concave rib-spinal angle the better results at 2-5 year. Muscular factors that may trigger/exacerbate the apical spinal deformity of scoliosis need more research. The concept that AIS pathogenesis involves putative neuromuscular dysfunction that deforms an immature spine is considered likely by several workers.

The NOTOM hypothesis for idiopathic scoliosis: is it nullified by the delayed puberty of female rhythmic gymnasts and ballet dancers with scoliosis?

Nachemson suggested that there are more girls than boys with progressive adolescent idiopathic because of a different timing between skeletal maturation and postural maturation in the sexes during adolescence. We termed Nachemson's concept the neuro-osseous timing of maturation (NOTOM) hypothesis and used it to propose a possible medical treatment for idiopathic scoliosis by delaying puberty through the pituitary using gonadorelin analogues as in idiopathic precocious puberty. The prevalence of scoliosis is reported to be increased in rhythmic gymnasts (RGs) in Bulgaria and in ballet dancers (BDs) in the USA. Both groups exhibit delayed puberty, which, at first sight, nullifies the NOTOM hypothesis for idiopathic scoliosis. While constitutional and environmental factors may determine these scolioses, the different curve types in RGs and BDs suggest that the exercise pattern over many years determines which type of scoliosis develops, although not the curve severity. We support the view that scoliotic RGs should be included in a group of sports-associated scoliosis separate from idiopathic scoliosis. Hence the delayed puberty of RGs and BDs with scoliosis does not nullify the NOTOM hypothesis as their scolioses are not idiopathic. There is a need to focus research on such subjects who have defined constitutional and environmental factors related to their scolioses.

Preliminary study of a new real-time ultrasound method for measuring spinal and rib rotation in preoperative patients with adolescent idiopathic scoliosis

A portable ultrasound machine with a linear array transducer was used by one observer (ASK) to evaluate the reproducibility for each of spinal (laminal) rotation and rib rotation in 13 preoperative patients with AIS (thoracic 7, thoracolumbar 6, mean Cobb angle 50 degrees, right 9, left 4, age 15.4 years, girls 10). With the subject in a prone position and her head supported, readings of spinal (laminal) and rib rotations were made directly on the back at 18 and 12 levels respectively. The subject was repositioned after walking around the room and a second set of spinal and rib rotations obtained (repeats). Conclusious. Repositioning the patient significantly alters some single level readings of lam inal rotation and rib rotation. Although the mean average spinal rotation and rib rotation each have acceptable reproducibility, repositioning the patient significantly alters the findings. In the appraisal of surgery by ultrasound the positional change reported here for (I) single level laminal rotation and rib rotation, and (2) mean average rotation imposes caution on the interpretation of the findings. The method enables the axial spine-nh rotation differences to be evaluated which is the subject of a separate paper.

Back shape assessment in each of three positions in preoperative patients with adolescent idiopathic scoliosis: evaluation of a 10-level Scoliometer method interpolated to 18-levels

A Scoliometer was used by one observer (RKP) to assess the reproducibility of angle of trunk inclinations (ATIs) in 13 preoperative patients with AIS (thoracic 7, thoracolumbar 6, mean Cobb angle 50 degrees, right 9, age 15.4 years, girls 10). Three positions were used namely standing forward-bending, (FB) sitting FB and prone. Readings of ATI on the back were obtained at each of 10 levels (T1-S1). The subject was repositioned after walking around the room and a second set of readings obtained (repeats). All readings were converted by a computer program to 18 levels and plotted. The readings from 18 levels were analysed by level, as well as summated and averaged both without and with correction for the side of the curve. Conclusions. Back surface asymmetry measured with a Scoliometer in these preoperative patients with AIS is less in the prone position than in each of the forward bending positions. The standing FB position has the best reproducibility which supports the practice of using this position to measure Scoliometer ATIs in preoperative patients with AIS.

Changes in surface and radiographic deformity after Universal Spine System for right thoracic adolescent idiopathic scoliosis: is rib-hump reassertion a mechanical problem of the thoracic cage rather than an effect of relative anterior spinal overgrowth?

STUDY DESIGN

Analysis of preoperative, 8-week, 1-year, and 2-year data from patients with right thoracic adolescent idiopathic scoliosis treated by posterior Universal Spine System (Stratec Medical, Oberdorf, Switzerland).

OBJECTIVE

Report 2-year results and the association between back surface and radiographic assessments.

SUMMARY OF BACKGROUND DATA

Few longitudinal studies have related surface and radiographic data in the follow-up of surgical patients.

METHODS

Of 34 patients with right thoracic adolescent idiopathic scoliosis having posterior Universal Spine System instrumentation, 27 had complete prospective back surface and radiographic appraisal.

RESULTS

Cobb angle corrected from 58 degrees to 34 degrees (41%), apical vertebral rotation from 26 degrees to 20 degrees (23%), apical vertebral translation from 4.5 to 2.4 cm (47%), and maximum angle of trunk inclination from 17 degrees to 13 degrees (22%) (preoperative to 2 years). Rib-hump reassertion occurred between 8 weeks and 1 year, regardless of age, and correlated with changes in vertebral translation (for 10 vertebral levels corresponding to 10 back surface levels between C7 and S1, P = 0.001 MANOVA). Preoperative frontal tilt of L1 with concave fifth rib-spinal angle predicted the percentage correction of maximum angle of trunk inclination, and the concave ninth rib-spinal angle predicted reassertion of maximum angle of trunk inclination.

CONCLUSIONS

Almost half of initial back surface correction is lost by 2 years. Segmental vertebral translation measurements most strongly correlate with segmental angle of trunk inclination measurements during follow-up. Rib-hump reassertion is best explained by unwinding of the thoracic cage tensioned by surgery rather than through relative anterior spinal overgrowth. Spine and thoracic cage factors determine rib-hump correction, so surgical disruption of the latter by costoplasty may prevent rib-hump reassertion. Results of scoliosis surgery should include surface data.

Luque trolley and convex epiphysiodesis in the management of infantile and juvenile idiopathic scoliosis

STUDY DESIGN

Retrospective analysis of 5-year follow-up data from patients instrumented with Luque trolley with or without convex epiphysiodesis for management of progressive infantile and juvenile idiopathic scoliosis.

OBJECTIVE

To assess results, establish predictors of outcome, and suggest more effective surgical interventions.

SUMMARY OF BACKGROUND DATA

Initial results have been reported. There are no long-term follow-up studies.

METHODS

Luque trolley instrumentation was used in eight patients with idiopathic scoliosis between 1983 and 1984. Luque trolley with convex epiphysiodesis was used in 18 patients between 1984 and 1990.

RESULTS

Changes in Cobb angle from 8-week to 5-year follow-up are as follows. For Luque trolley alone, Cobb angle worsened for all patients. For progressive infantile scoliosis managed with Luque trolley and convex epiphysiodesis, Cobb angle worsened in seven, remained unchanged in four, and improved in two patients. Mean age at operation was 3.1 years (range, 1.5-7.4 years), and instrumented spinal growth was 32% of expected growth. Preoperation Cobb angle was 65 degrees (range, 40-95 degrees). Cobb angle at 5-year follow-up was 32 degrees (range, 0-86 degrees), which is predicted by preoperation apical concave rib-spinal angle (P = 0.002) and upper end vertebral tilt (P = 0.04). For juvenile idiopathic scoliosis managed with Luque trolley and convex epiphysiodesis, Cobb angle worsened in three patients and improved in one.

CONCLUSIONS

Luque trolley instrumentation alone does not prevent curve progression. Additional convex epiphysiodesis results in curve resolution in some patients, which suggests a growth effect. Both spine and rib factors predict Cobb angle at 5-year follow-up.

Posterior instrumentation in scoliosis

The aims of posterior fusion and instrumentation in scoliosis are to achieve and maintain correction of the deformity and balance the spine in three planes, whilst keeping the fusion as short as possible and protecting the spinal cord. Harrington developed the first generation of posterior instrumentation, which considered only frontal plane correction. Since that time there has been an evolution from biplanar correction, addressing the frontal plane and sagittal plane, to triplanar correction, also addressing spinal derotation, and, most recently, to segmental derotation of strategic vertebral bodies.

A segmental analysis of thoracic shape in chest radiographs of children. Changes related to spinal level, age, sex, side and significance for lung growth and scoliosis

Thoracic ratios (TRs) were measured segmentally (T1-12) in the chest radiographs of 412 children aged 0-17 years attending hospital with minimal disorder or diseases (boys 193, girls 219). A new method for measuring TRs was used which calculates the width of the left hemithorax, the right hemithorax and the total thorax relative to T1-T12 distance. The data were analysed in 3 age groups--infancy, childhood and puberty, after the classification of Karlberg (1989). The findings are as follows. 1. The chest broadens from T1 to about T10-11. 2. Between infancy and childhood, relative to its length the chest narrows from above downwards and particularly in the lower chest (T5-12 average diminution, boys 9.5%, girls 9.8%). In the upper chest, the narrowing is more marked in girls than boys (T1-4 average diminution, boys 5.1%, girls 8.2%). 3. Between childhood and puberty, the girl's but not the boy's chest narrows further in its lower half (below T6 average diminution 3.3%). At T6 and above there is no detectable change in the relative width of the chest in either boys or girls. 4. The relative narrowing of the chest during growth appears to result from several mechanisms: (1) elevation of upper rib-vertebra angles (above 90 degrees); (2) drooping of lower rib-vertebra angles (below 90 degrees); and (3) linear rib growth being impaired relative to thoracic spinal growth in the lower ribcage (T6-12) of girls between childhood and puberty (Grivas et al. 1991 d). 5. The hypothesis is suggested that the relative narrowing of the lower chest with increasing age reduces the rotational inertia of the thorax in gait. There is a greater need for such reduction in girls because of the greater rotational inertia generated by the mass of their larger pelves. This hypothesis provides a mechanical explanation for the proportionate change in the girl's lung in the later stages of growth (Simon et al. 1972). 6. Developmentally, the left hemithorax is ahead of the right hemithorax in childhood. 7. Thoracic asymmetry favouring the right chest is found, and more so in puberty than childhood which is connected with the larger size of the thorax and lung in the adult. 8. The evidence suggests that hemithoracic development is caudocranial; this is consistent with an adaptation of the human ribcage to control spinal rotation and counterrotation when bipedal gait was acquired in evolution. 9. In progressive infantile idiopathic scoliosis, the upper chest is funnel-shaped.(ABSTRACT TRUNCATED AT 400 WORDS)

The operative treatment of progressive early onset scoliosis. A preliminary report

Thirteen patients with progressive early onset scoliosis have been managed operatively in an attempt to achieve correction without bracing and to allow the spine to grow. All had posterior segmental spinal instrumentation (SSI) without fusion and 9 of 13 had anterior apical growth arrest as a separate additional procedure. At 2-year follow-up, curve correction averaged 46%. Patients who had anterior apical growth arrest and SSI without fusion had less curve deterioration than those who had SSI alone. New methods are described for 1) measuring growth of the instrumented segment of the spine and 2) calculating the predicted growth of the instrumented segment. Eight of the 13 had more than 50% of predicted growth, three had 30-50% of predicted growth, and two had less than 30% of predicted growth. Operative treatment has been successful in the short term in all but the most malignant form of infantile idiopathic scoliosis.

An analysis of the effect of the Zielke operation on S-shaped curves in idiopathic scoliosis. A follow-up study revealing some skeletal and soft tissue factors involved in curve progression

This article analyzes the fate of S-shaped idiopathic spinal curves during follow-up in 18 patients having the Zielke VDS operation. The spinal radiographs were evaluated by Cobb angle, end-vertebra angles (EVAs), vertebral rotation, and by a new method using the tilt of the surgically fused spinal block in the frontal plane. Spinal growth was measured. Using the conventional criterion for Cobb angle progression, 83% of the lower curves and 50% of the upper curves progress. The use of EVAs shows that progression occurs mainly in the middle (thoracolumbar) segment of the spine. Curve progression occurs in the frontal plane without any significant change in vertebral rotation. The progression of the upper curve Cobb angle is not related to the progression of the Cobb angle of the lower curve; but it is related to 1) tilt of the spinal block, 2) growth of the spine below the block and 3) overall linear spinal growth (T1-S1). Progression of the upper EVA of the upper curve is associated with skeletal immaturity. The key features leading to curve progression after the Zielke operation appear to be spinal asymmetry in the frontal plane, linear spinal growth, and concave lumbar muscle tether (myostatic contracture). The surgical implications of the findings are outlined.

Harrington-Luque and Cotrel-Dubousset instrumentation for idiopathic thoracic scoliosis. A postoperative comparison using segmental radiologic analysis

This article reports a comparison of the Cotrel-Dubousset (CD) operation with the Harrington-Luque (HL) procedure for the treatment of adolescent idiopathic thoracic scoliosis. Thirty-nine patients were studied preoperatively and postoperatively using segmental radiologic measurements including Cobb angle, end-vertebra angles (EVAs), surgical flexibility index, vertebral rotation, displacement and tilt, convex and concave rib-vertebra angles (RVAs), and kyphosis and lordosis. Cotrel-Dubousset is not significantly different from HL with respect to Cobb angle (%), surgical flexibility index, apical vertebral displacement, apical vertebral rotation, apical rib-vertebra angles, kyphosis, and lordosis. It is significantly better than the HL with respect to the correction of vertebral displacement at T10-11; lower EVA of the thoracic curve; vertebral rotation mainly above the apex; convex RVAs above the apex; and concave RVAs at T10. The surgical correction of vertebral tilt above and below the apex of the thoracic curve is significantly related to the correction of convex and concave RVAs. The view that persistent deformity of ribs is a factor needing surgical correction in some patients with adolescent idiopathic thoracic scoliosis having posterior instrumentation and fusion needs further evaluation.

Femoral anteversion in healthy children. Application of a new method using ultrasound

Femoral anteversion (torsion) was measured in 219 healthy children aged 1-15 years (boys 128, girls 91). The hips and knees were examined using a standard static-image B-mode compound scanner. The torsion in each femur was calculated. The findings show: (1) A significant negative correlation between femoral anteversion and age (r = -0.43), with only 8-22% being accounted for by age (r2 value). (2) A significant correlation between anteversion of the two femora (r = 0.77). (3) No sex difference for femoral anteversion and its asymmetry. (4) Marked degrees of femoral anteversion asymmetry (more than 10 degrees) show a pattern suggesting a relation to age, side and possibly sex. (5) Abnormal femoral anteversion asymmetry in 12 children, there being an excess of children with orthopaedic symptoms and signs in the group with femoral anteversion outside 2 S.D. (6) A relation between anteversion asymmetry and foot length/tibial length ratio. (7) No relation of femoral anteversion to social class, order in family, parental age at birth of child, birth weight and presentation. (8) A significant correlation of femoral anteversion between siblings (r = 0.66).

An analysis of the effect of the Zielke operation on the rib cage of S-shaped curves in idiopathic scoliosis

This report evaluates the rib cage in 16 patients with S-shaped idiopathic scoliosis having the Zielke operation and followed-up for an average period of 30 months. Methods used include Cobb angle and a segmental evaluation (T7-T12) of each of convex and concave rib-vertebra angles (RVAs), rib-vertebra angle differences (RVADs), vertebral rotation, tilt and displacement. Preoperatively, the apical convex ribs droop more than the concave ribs, but the most striking difference is an asymmetry of RVAs, with increasing droop of the concave RVAs from T7-T12. The effect of the Zielke operation (on the lower curve) is: (a) to correct the Cobb angle, vertebral tilt, and displacement of the upper (thoracic) curve; (b) to derotate the spine; (c) to elevate the mobile concave ribs; (d) to have little or no effect on the stiff apical convex ribs; and (e) to increase the droop of the mobile lower convex ribs. During follow-up, six of the upper (thoracic) curves progressed. The apical RVAD and apical convex RVA are not prognostic. The concave RVAs maintain their position while convex RVAs elevate relative to the concave ribs.

An analysis of the effect of the Zielke operation on S-shaped curves in idiopathic scoliosis. The use of EVAs showing that correction of the thoracic curve occurs in its lower part: significance of the thoracolumbar spinal segment

This paper analyzes the initial effect of the Zielke VDS operation on S-shaped idiopathic spinal curves in 17 patients with particular reference to the thoracic spine. The curves are evaluated by conventional methods (Cobb angle, apical vertebral rotation, kyphosis, and lordosis) and by a new method using end vertebra angles (EVAs). Three new surgical correction indices are used. In the lower curve, the surgical correction averaged 81%, and it is usually larger than that induced in the thoracic curve by about 48% (surgical correctability index). The lower curve correction is asymmetric, occurring more in its lower part (lower EVA) than in its upper part (upper EVA), a difference that the authors attribute to the restraint imposed by the rib cage on the upper EVA of the lower curve. In the upper (thoracic) curve, the surgically induced correction is variable and averages 33% (range, 6-69%). It is related significantly to preoperative bending film flexibility. The thoracic curve correction also is asymmetric, occurring more in its lower part (lower EVA) than in its upper part (upper EVA), which usually remains stable. The kyphosis angle decreases by an average of 7 degrees. The thoracic apical vertebral rotation shows variable changes. The findings show that the correction of the upper curve occurs mainly in the thoracolumbar spinal segment. It is suggested that this junctional segment of the spine is of importance in determining the limits of both instrumentation and fusion for idiopathic scoliosis.

Variation in vertebral levels of the vertebra prominens and sacral dimples in subjects with scoliosis

The vertebra prominens is found most frequently at C7 in both sexes (78.7% of 47 females, 58.8% of 17 males). It is frequently at T1 in females (3 of 47: 6.4%) though not uncommonly so in males (6 of 17: 35%). The first spinous process felt at the lower end of the nuchal furrow is an unreliable guide to the vertebra prominens in the female (being at C6 in 59.6% of female subjects and coinciding with the vertebra prominens in only 46.8%). The sacral dimples have a wide distribution in vertebral level and are unreliable as surface vertebral landmarks. The generally accepted vertebral level of sacral dimples being at S2 is disputed, being present at this level in only 5 of 68 subjects (7.4%). There is a significant sex difference in the location of sacral dimples, being higher relative to vertebrae in females than in males, P less than 0.05. This finding is related particularly to the greater pelvic height of adolescent girls compared with boys.

Hump changes on forward flexion of the lumbar spine in patients with idiopathic scoliosis. A study using ISIS and the Scoliometer in two standard positions

A detailed study of the effects of forward flexion in the spine on back shape is reported. ISIS and the Scoliometer were used to record angle of trunk inclinations (ATIs) in 13 patients with idiopathic scoliosis. Two standard positions were used: standing erect (for ISIS) and sitting forward bending (for the Scoliometer). In the lumbar region, a positional change in ATI between standing erect and sitting forward is revealed; it is related to the type and side of mainly compensatory spinal curves. It does not correlate with Cobb angle but it does correlate with each of spinous process rotation (Bunnell) and pedicular rotation (Perdriolle). In the thoracic region, the change from a standing-erect to a sitting-forward-bending position, in contrast, shows a statistically significant reduction of the hump on the convexity of the spinal curve. The findings have relevance to screening tests for scoliosis.