Adult scoliosis: a quantitative radiographic and clinical analysis

STUDY DESIGN

Prospective analysis of a consecutive series of adult patients with adolescent idiopathic scoliosis of the adult and de novo degenerative scoliosis.

OBJECTIVES

To clinically and radiographically study two populations of adult patients with either adolescent idiopathic scoliosis of the adult or de novo degenerative scoliosis in a quantitative manner to identify reliable radiographic parameters that correlate with clinical symptoms.

SUMMARY AND BACKGROUND

Although there are many causes of spinal deformity in the adult, there are two main categories of adult scoliosis: adolescent idiopathic scoliosis of the adult and de novo degenerative scoliosis. Unlike pediatric scoliosis, in adults there are no established radiographic parameters or classification systems that reliably provide a clinical correlation or offer a useful language for communication among specialists. This study gathered complete clinical and radiographic information on 95 patients with adult scoliosis and established several radiographic parameters that correlated with clinical symptoms.

METHODS

Each of the 95 patients completed a clinical questionnaire that included a self-reported visual analog scale and underwent full-length standing anteroposterior and lateral radiography. Radiographic analysis was performed by use of digital analysis and included measurement of the Cobb angle, the number of vertebrae in each curve, plumbline offset from T1 to the midsacral line, the upper endplate obliquities of L3 and L4, and maximal lateral olisthy between two adjacent lumbar vertebrae. Sagittal plane measurements included lumbar lordosis, thoracolumbar kyphosis, and the Sagittal Pelvic Tilt Index. Statistical analysis of both radiographic and clinical parameters of pain was performed to determine any significant correlations between the two.

RESULTS

This study showed that lateral vertebral olisthy, L3 and L4 endplate obliquity angles, lumbar lordosis, and thoracolumbar kyphosis were significantly correlated with pain.

CONCLUSION

This quantitative analysis identified several clinically relevant radiographic parameters in adult scoliosis patients. Additionally, excellent predictive formulas for self-reported pain levels were obtained.

Pathology of the vitamin C deficiency syndrome in channel catfish (Ictalurus punctatus)

Channel catfish fingerlings fed purified diets devoid of vitamin C showed reduced growth rate, deformed spinal columns, external and internal hemorrhages, erosion of fins, dark skin color and reduced bone collagen content after 8 to 12 weeks, whereas fish fed a diet containing 30 mg/kg of vitamin C had none of these anomalies after 22 weeks. A dietary level of 30 mg of vitamin C per kg was insufficient to prevent distortion of gill filament cartilage, although 60 mg of vitamin C per kg was sufficient. Vertebral collagen percentages of 25 or below and liver ascorbic acid levels of 30 microgram/g or below appeared to be indicative of vitamin C deficiency in channel catfish fingerlings. Epidermis and dermis were almost completely healed and extensive collagen fiber formation had commenced in the somatic muscle, in experimentally inflicted wounds after 10 days in fish fed the vitamin C-free diet. Skin and muscle at the wound site were almost regenerated to normal after 10 days in fish fed 60 mg of vitamin C per kg of diet.

A pedicle screw construct gives an enhanced posterior correction of adolescent idiopathic scoliosis when compared with other constructs: myth or reality

STUDY DESIGN

Tricenter retrospective cohort study of 72 patients who underwent posterior correction of Lenke 1 adolescent idiopathic scoliosis (AIS). Each center represented a single surgeon using only one type of construct.

OBJECTIVE

Compare the initial postoperative and 2-year follow-up correction of Lenke 1 AIS curves, after accounting for the preoperative flexibility of the curves.

SUMMARY OF BACKGROUND DATA

There are multiple reports in literature of the enhanced posterior corrective ability of the pedicle screw in the treatment of AIS. Unfortunately, none of these reports took into account the preoperative flexibility of the curve. It stands to reason that rigid curves will not correct as much as flexible curves irrespective of the nature of the construct.

METHODS

Groups were as follows: Group 1 (proximal and distal hooks and segmental intraspinous collar button wires), 24 patients; Group 2 (proximal hooks, distal screws, and apical sublaminar wires), 23 patients; and Group 3 (pedicle screws only), 25 patients. The postoperative correction percentage was expressed as a ratio of the preoperative flexibility and was termed Cincinnati correction index (CCI). Mathematically speaking the CCI equals (postoperative correction/preoperative erect Cobb angle) divided by (supine bending preoperative correction/preoperative erect Cobb angle). The postoperative sagittal correction was also measured.

RESULTS

CCI 2 (at 2-year follow-up) for Group 1 was 1.71, for Group 2 was 1.34, and for Group 3 was 1.41. The differences were not statistically significant. Within Group 1, however, there was a statistically significant difference between CCI (1.95) and CCI 2 (1.71), indicating a statistically significant loss of correction over 2 years. However, in terms of absolute values, there was only a 4 degree (average) difference between the initial and the 2-year postoperative Cobb measurement, rendering the loss off correction clinically insignificant. No such statistically or clinically significant differences were noted within Groups 2 and 3. Group 1 and Group 3 constructs further lordosed the curve by 8 degrees and 11 degrees, respectively, whereas the Group 2 construct retained or marginally increased the preoperative kyphosis.

CONCLUSION

The Group 3 (pedicle screw only) construct did not give an enhanced correction of Lenke 1 AIS, when the preoperative flexibility of the curve was considered. Also, contrary to popular belief, the pedicle screw construct has a lordosing effect on the thoracic spine. Therefore, we think that there is no significant advantage in using a relatively expensive pedicle screw construct in the correction of Lenke 1 AIS.

Circumferential lumbar spinal fusion with Brantigan cage versus posterolateral fusion with titanium Cotrel-Dubousset instrumentation: a prospective, randomized clinical study of 146 patients

STUDY DESIGN

A prospective randomized clinical study with a 2-year follow-up period was conducted.

OBJECTIVE

To analyze the effects of circumferential fusion using ALIF radiolucent carbon fiber cages and titanium posterior instrumentation on functional outcome, fusion rate, complications, and lumbar lordosis.

SUMMARY OF BACKGROUND DATA

Circumferential fusion has become a common procedure in lumbar spine fusion, both as a primary and salvage procedure. However, the claimed advantages of ALIF plus PLF over conventional PLF lack scientific documentation.

METHODS

From April 1996 through November 1999, a total of 148 patients with severe chronic low back pain were randomly selected for either posterolateral lumbar fusion with titanium CD-Horizon (posterolateral group) or circumferential fusion with a ALIF Brantigan cage plus posterior instrumentation. The Dallas Pain Questionnaire (DPQ), the Low Back Pain Rating Scale (LBPR), and a questionnaire concerning work status assessed their outcomes.

RESULTS

Both groups showed highly significant improvement in all four categories of life quality (DPQ) as well as in the back pain and leg pain index (LBPR), as compared with preoperative status. There was a clear tendency toward better overall functional outcome for patients with the circumferential procedure ( < 0.08), and this patient group also showed significantly less leg pain at the 1-year follow-up evaluation ( < 0.03) and less peak back pain at 2 years ( < 0.04). Sagittal lordosis was restored and maintained in the circumferential group ( < 0.01). The circumferential fusion patients showed a higher posterolateral fusion rate (92%) than the posterolateral group (80%)( < 0.04). The repeat operation rate including implant removal was significantly lower in the circumferential group (7%) ( < 0.009) than in the posterolateral group (22%).

CONCLUSIONS

Circumferential lumbar fusion restored lordosis, provided a higher union rate with significantly fewer repeat operations, showed a tendency toward better functional outcome, and resulted in less peak back pain and leg pain than instrumented posterolateral fusion. The clinical perspective of the current study implies a recommendation to favor circumferential fusion as a definitive surgical procedure in complex lumbar pathology involving major instability, flatback, and previous disc surgery in younger patients, as compared with posterolateral fusion with pedicle screws alone.

Clinical outcomes of 3 fusion methods through the posterior approach in the lumbar spine

STUDY DESIGN

This prospective randomized study compared 3 fusion methods: posterolateral fusion (PLF), posterior lumbar interbody fusion (PLIF), and PLIF combined with PLF (PLF+PLIF).

OBJECTIVES

To compare the outcomes of the 3 fusion methods and find a useful fusion method.

SUMMARY OF BACKGROUND DATA

Many studies have shown clinical results, advantages, and postoperative complications of each fusion method, but few have compared the 3 fusion methods prospectively.

METHODS

A total of 167 patients who underwent 1 or 2-level fusion surgery because of degenerative lumbar disease from January 1996 to September 2000 were studied. Minimum follow-up was 3 years. The patients were randomized into 1 of 3 treatment groups: group 1 (PLF; n = 62); group 2 (PLIF; n = 57); and group 3 (PLF+PLIF; n = 48). A visual analog scale, the Oswestry Disability Questionnaire, and Kirkaldy-Willis criteria were used to measure low back pain, leg pain, and disability. For radiologic evaluation, disc height, lumbar lordosis, segmental angle, and bone union were examined. Postoperative complications were also analyzed.

RESULTS

At the last follow-up, good or excellent results were obtained in 50 cases of PLF (80.7%), 50 cases of PLIF (87.8%), and 41 cases of PLF+PLIF (85.5%). No statistical differences were found among the 3 groups (P = 0.704). All methods indicated significant improvement in the disc height (P < 0.05), with PLF having the highest loss in disc height. Lumbar lordosis and segmental angle increased significantly, and improvement of the segmental angle in the 3 fusion methods had statistically significant differences. The nonunion rates at the last follow-up in the 3 fusion groups were not statistically significant, with 8% in group 1, 5% in group 2, and 4% in group 3 (P > 0.05). Complications included deep infection in 3 cases, transient nerve palsy in 4, permanent nerve palsy in 1, and donor site pain in 6.

CONCLUSIONS

No significant differences in clinical results and union rates were found among the 3 fusion methods. PLIF had better sagittal balance than PLF. PLIF without PLF had advantages of the elimination of donor site pain, shorter operating time, and less blood loss.

Sagittal plane analysis of adolescent idiopathic scoliosis: the effect of anterior versus posterior instrumentation

STUDY DESIGN

Radiographic analysis of anterior and posterior instrumentation for adolescent idiopathic scoliosis.

OBJECTIVES

To compare effects of anterior versus posterior instrumentation on sagittal plane parameters.

SUMMARY OF BACKGROUND DATA

The sagittal plane is critical to the long-term success of scoliosis surgery, but few studies have compared the effect of anterior versus posterior instrumentation.

METHODS

Standing, full spine lateral radiographs of 110 consecutive patients (mean age 14 years) who had surgery for adolescent idiopathic scoliosis between 1996 and 1998 at one institution with a minimum 24-month (mean 32 months) follow-up were evaluated. Fifty patients were instrumented anteriorly with single screw-rod constructs. Sixty patients were instrumented posteriorly with segmental implants (5.5 mm; hooks, wires, and/or pedicle screws).

RESULTS

At the final follow-up, the proximal junctional measurement (measured between the proximal instrumented vertebra and the segment two levels cephalad) increased most with posterior instrumentation (+7 degrees increase for posterior thoracic +1 degrees increase for anterior thoracic instrumentation, P= 0.02; +9 degrees increase for posterior thoracic and lumbar instrumentation vs. +4 degrees for anterior thoracolumbar instrumentation, P= 0.03). Thoracic kyphosis (T5-T12) increased significantly with anterior versus posterior thoracic instrumentation (+4 degrees vs. -2 degrees change, P= 0.04). Lumbar lordosis (T12-S1) was enhanced with either anterior or posterior instrumentation. No significant changes in distal junctional measurement (measured between the distal instrumented vertebra and the segment two levels caudal) were noted. The C7 sagittal plumbline remained negative in all groups at the final follow-up.

CONCLUSION

Anterior and posterior instrumentation had differential effects on the sagittal plane in patients with adolescent idiopathic scoliosis. However, the overall magnitude of the differences was small. Properly performed, both approaches can result in acceptable sagittal profiles.

Classification of high-grade spondylolistheses based on pelvic version and spine balance: possible rationale for reduction

STUDY DESIGN

Retrospective review of a radiographic database of high-grade spondylolisthesis patients in comparison with asymptomatic controls.

OBJECTIVE

To analyze the sagittal spinopelvic alignment in high-grade spondylolisthesis patients and identify subgroups that may require reduction to restore sagittal balance.

SUMMARY OF BACKGROUND DATA

High-grade spondylolisthesis is associated with an abnormally high pelvic incidence (PI); however, the spatial orientation of the pelvis, determined by sacral slope (SS) and pelvic tilt (PT), is not known. We hypothesized that sagittal spinal alignment would vary with the pelvic orientation.

METHODS

Digitized sagittal radiographs of 133 high-grade spondylolisthesis patients (mean age, 17 years) were measured to determined sagittal alignment. K-means cluster analysis identified 2 groups based on the PT and SS, which were compared by paired t test. Comparisons were made to asymptomatic controls matched for PI.

RESULTS

High-grade spondylolisthesis patients had a mean PI of 78.9 degrees +/- 12.1 degrees . Cluster analysis identified a retroverted, unbalanced pelvis group with high PT (36.5 degrees +/- 8.0 degrees )/low SS (40.3 degrees +/- 9.0 degrees ) and a balanced pelvic group with low PT (mean 21.3 degrees +/- 8.2 degrees )/high SS (59.9 degrees +/- 11.2 degrees ). The retroverted pelvis group had significantly greater L5 incidence and lumbosacral angle with less thoracic kyphosis than the balanced pelvic group. A total of 83% of controls had a "balanced pelvis" based on the categorization by SS and PT.

CONCLUSION

Analysis of sagittal alignment of high-grade spondylolisthesis patients revealed distinct groups termed "balanced" and "unbalanced" pelvis. The PT and SS were similar in controls and balanced pelvis patients. Unbalanced pelvis patients had a sagittal spinal alignment that differed from the balanced pelvis and control groups. Treatment strategies for high-grade spondylolisthesis should reflect the different mechanical strain on the spinopelvic junction in each group; reduction techniques might be considered in patients with an unbalanced pelvis high-grade spondylolisthesis.

Dynamic sagittal imbalance of the spine in degenerative flat back: significance of pelvic tilt in surgical treatment

STUDY DESIGN

A retrospective study of 26 patients with degenerative flat back treated with corrective osteotomy.

OBJECTIVE

To analyze dynamic sagittal imbalance and to elucidate the cause of postoperative persistent stooping in degenerative flat back.

SUMMARY OF BACKGROUND DATA

Sagittal spinal imbalance in degenerative flat back was more evident on walking, suggesting its dynamic nature. The most puzzling complication in its surgical treatment was postoperative persistent stooping.

METHODS

This study analyzed 26 surgically treated patients with preoperative gait analysis. Patients were divided into two groups according to postoperative improvement in stooping: Group 1 with marked improvement in stooping and Group 2 with persistent stooping. Various radiographic and gait parameters were compared between the two groups.

RESULTS

Comparison of radiographic parameters, representing the static status of the spine, did not indicate any clue to the mechanism for persistent stooping. However, comparison of gait parameters, representing the dynamic status of the spine, revealed meaningful differences between the two groups. Among various gait parameters compared, pelvic tilt seemed to be the most important clue. Patients in Group 1 showed posterior pelvic tilt, whereas those in Group 2 showed marked anterior pelvic tilt.

CONCLUSION

Degenerative flat back could be classified into two types based on pelvic position during walking: one with posterior pelvic tilt and the other with marked anterior pelvic tilt. In the former type, corrective surgery improved the stooping. In the latter, corrective surgery was ineffective, resulting in postoperative persistent stooping.

Aetiology of idiopathic scoliosis: current concepts

The aetiology of the three-dimensional spinal deformity of idiopathic scoliosis (IS) is unknown. Progressive adolescent idiopathic scoliosis (AIS) that mainly affects girls is generally attributed to relative anterior spinal overgrowth from a mechanical mechanism (torsion) during the adolescent growth spurt. Established biological risk factors to AIS are growth velocity and potential residual spinal growth assessed by maturity indicators. Spine slenderness and ectomorphy in girls are thought to be risk factors for AIS. Claimed biomechanical susceptibilities are (1) a fixed lordotic area and hypokyphosis and (2) concave periapical rib overgrowth. MRI has revealed neuroanatomical abnormalities in approximately 20% of younger children with IS. A neuromuscular cause for AIS is probable but not established. Possible susceptibilities to AIS in tissues relate to muscles, ligaments, discs, skeletal proportions and asymmetries, the latter also affecting soft tissues (e.g. dermatoglyphics). AIS is generally considered to be multi-factorial in origin. The many anomalies detected, particularly left-right asymmetries, have led to spatiotemporal aetiologic concepts involving chronomics and the genome altered by nurture without the necessity for a disease process. Genetic susceptibilities defined in twins are being evaluated in family studies; polymorphisms in the oestrogen receptor gene are associated with curve severity. A neurodevelopmental concept is outlined for the aetiology of progressive AIS. This concept involves lipid peroxidation and, if substantiated, has initial therapeutic potential by dietary anti-oxidants. Growth saltations have not been evaluated in IS.

Analysis of cervical spine curvature in patients with cervical spondylosis

Computer-aided design techniques were used to analyze the degree of spinal curvature shown on cervical spine radiograms of 28 patients. On films standardized as to size, a geometrical chord was constructed from the 2nd to the 7th cervical vertebrae (C2 to C7), and an arc was drawn along the posterior margin of the vertebrae. The resulting area was used as an index of curvature, and the spinal canal diameter was measured. Severity of myelopathy as well as clinical improvement was related to the geometrical data. There was no clear correlation between severity of the preoperative myelopathy and degree of curvature. Severe myelopathy was seen in association with straight, lordotic, and hyperlordotic spines. Neck pain was most severe in patients with reversed cervical curvature. The degree of curvature, however, seems to relate to the postoperative clinical outcome. Patients with relatively normal curvature showed the greatest improvement in symptoms and signs. Postoperative magnetic resonance scanning confirms that posterior migration of the spinal cord after laminectomy may be inadequate to clear osteophytes in patients with straightened or reversed curvature of the cervical spine. Spinal geometry should be considered in the selection of the best surgical procedure and the extent of laminectomy for patients with spondylotic myelopathy. Significant abnormalities of spinal curvature may account for some instances of poor outcome after laminectomy.

Impact of postural deformities and spinal mobility on quality of life in postmenopausal osteoporosis

The objective of the study was to evaluate the impact of postural deformities and spinal mobility on quality of life (QOL) in patients with spinal osteoporosis. A total of 157 postmenopausal women aged over 60 years with osteoporosis were divided into five groups according to their postural deformities: round back (RB, n=41), hollow round back (HRB, n=33), whole kyphosis (WK, n=40), lower acute kyphosis (LAK, n=18), and normal posture (NP, n=25). QOL was evaluated using the Japanese Osteoporosis QOL Questionnaire (JOQOL) proposed by the Japanese Society for Bone and Mineral Research. This questionnaire contains six domains, with higher scores indicating higher levels of QOL. The number of vertebral fractures, thoracic kyphosis and lumbar lordosis angles, and spinal range of motion (ROM) during maximum flexion and extension were also measured with radiographs. Total QOL scores in RB, HRB, WK, and LAK groups were significantly lower than those in the NP group, and those in WK group were even lower compared with the other groups ( P<0.05). All the groups with postural deformities, but not the NP group, showed significant positive correlations between total QOL score and spinal ROM (0.521</= r</=0.747, P<0.05). Total QOL score showed a significant correlation with age, number of vertebral fractures, lumbar lordosis angle, and spinal ROM in a total of 157 patients. However, multiple regression analysis revealed that spinal ROM best correlated with total QOL score. We concluded that QOL in patients with osteoporosis was impaired by postural deformities, especially by whole kyphosis, and that spinal mobility has a strong effect on QOL in these patients.

Spinal bone mineral density measured with quantitative CT: effect of region of interest, vertebral level, and technique

This study documents the relationship between different vertebral bone compartments with quantitative computed tomography (CT). Four distinct patient groups were investigated: healthy pre- and early postmenopausal women as well as healthy and osteoporotic late postmenopausal women. Three different regions of interest (ROIs) were employed: the elliptical ROI located in the anterior trabecular portion of the vertebral body, the peeled ROI of irregular shape that circumscribes most of the trabecular bone, and the integral ROI including all bone except for the transverse processes. Both single- and dual-energy quantitative CT techniques were employed at T-12 through L-3. Correlation between measurements in the elliptical and peeled ROIs was high (r = .985). The authors concluded that either ROI is acceptable for clinical use. The decrements in bone mineral density (BMD) for the integral ROI were smaller than those for the elliptical ROI. Dual-energy measurements were consistently higher than single-energy measurements. BMD as a function of vertebral level decreased systematically from T-12 to L-3. However, the average density of T-12 through L-3 can be accurately predicted by the average density of L-1 and L-2 (r = .997). Precision did not deteriorate significantly when BMD was expressed as the average of L-1 and L-2 (1.5%) instead of T-12 through L-3 (1.4%). In this study the data suggest a modified quantitative CT protocol for clinical applications in which BMD of only L-1 and L-2 are measured at a fixed gantry tilt.

A retrospective radiographic analysis of subaxial sagittal alignment after posterior C1-C2 fusion

STUDY DESIGN

Subaxial sagittal alignment following atlantoaxial (A-A) posterior fusion was investigated retrospectively in patients with A-A subluxation.

OBJECTIVES

To evaluate the association between A-A fusion angle and postoperative subaxial sagittal alignment and to determine the optimal fusion angle for preservation of physiologic subaxial alignment.

SUMMARY OF BACKGROUND DATA

A-A posterior fusion has been used for patients with A-A instability and provided satisfactory clinical results. However, there are patients showing unexpected development of subaxial kyphosis after surgery. The reasons for subaxial kyphosis after A-A fusion remain unclear.

METHODS

Seventy-six patients with A-A subluxation who underwent several types of posterior A-A fusion were involved. There were 46 women and 30 men. The causes of A-A subluxation were rheumatoid arthritis in 47, trauma in 16, os odontoideum in 8, and unknown in 5. The methods of posterior fusion consisted of Magerl procedure with posterior wiring in 51, Brooks wiring in 18, and Halifax clamp in 7. Angles at C1-C2, C2-C7, and C1-C7 in the neural position were measured before surgery and at the final follow-up to find out any association between postoperative C2-C7 angle and the other radiologic parameters. The association between O-C1 range of motion and C2-C7 angle was also investigated.

RESULTS

The mean angles of C1-C2, C2-C7, and C1-C7 before surgery were 18.4 degrees, 14.5 degrees, and 32.9 degrees, respectively. Those at the final follow-up were 26.0 degrees, 5.5 degrees, and 31.5 degrees, respectively. These results indicated that C1-C2 fixation in a hyperlordotic position led to a subaxial kyphosis after surgery. Statistics showed that there was a linear association between the C1-C2 lordotic fixation angle and the C2-C7 kyphotic angle.

CONCLUSIONS

Surgical fixation of A-A joint in a hyperlordotic position will lead the lower cervical spine to a kyphotic sagittal alignment after surgery. To maintain the physiologic sagittal alignment of the subaxial cervical spine, C1-C2 should not be fixed in a hyperlordotic position.

Radiographic Analysis of Transforaminal Lumbar Interbody Fusion for the Treatment of Adult Isthmic Spondylolisthesis

The radiographs of 35 consecutive adult patients with isthmic spondylolisthesis who underwent a transforaminal lumbar interbody fusion (TLIF) with one or two Brantigan carbon fiber cages and pedicle screw instrumentation were evaluated. Anterolisthesis, disk space height, and slip angle were measured in preoperative and postoperative standing neutral radiographs. Anterolisthesis was reduced and disk space height was increased with the TLIF procedure. Average slip angle, however, was not significantly altered. The restoration of lordosis across the listhetic disk space correlated with a more anterior placement of the interbody cage within the disk space. The TLIF technique, performed with the Brantigan cage and pedicle screw instrumentation, appears to be able to restore disk height and reduce forward translation in patients with isthmic spondylolisthesis, but improvement in sagittal alignment is dependent upon anterior placement of the interbody device.

Pathophysiology of spinal deformities in neurofibromatosis. An analysis of seventy-one patients who had curves associated with dystrophic changes

The findings in seventy-one patients who had previously untreated spinal deformities associated with dystrophic changes and who had neurofibromatosis were reviewed to identify the risk factors for progression of the curve as well as the natural history of the dystrophic changes and curve patterns. Four different types of curves were evaluated. Two of them had the most severe progression: (1) kyphoscoliosis with angular kyphosis (gibbus) and marked dystrophic changes and (2) so-called kyphosing scoliosis (a scoliosis that has so much rotation [90 degrees] that progression is evident only on the lateral roentgenogram) with a round kyphosis. Risk factors for substantial progression of the curve were an early age of onset, a high Cobb angle at the first examination, an abnormal kyphosis, vertebral scalloping, severe rotation at the apex of the curve, location of the apex of the curve in the middle to caudal thoracic area, penciling of one rib or more on the concave side or on both sides of the curve, and penciling of four ribs or more.

The association between athletic training time and the sagittal curvature of the immature spine

Strenuous physical activity is known to cause structural abnormalities in the immature vertebral body. Concern that exposure to years of intense athletic training may increase the risk for developing adolescent hyperkyphosis in certain sports, as well as the known association between hyperkyphosis and adult-onset back pain, led us to examine the association between cumulative hours of athletic training and the magnitude of the sagittal curvature of the immature spine. A sample of 2,270 children (407 girls and 1,863 boys) between 8 and 18 years of age were studied. An optical raster-stereographic method was used to measure the mid-sagittal curvatures of the surface of the back while the subject was in the upright standing position to quantify the angles of thoracic kyphosis and lumbar lordosis. These data were then correlated with self-reported hours of training measured by interview and questionnaire. The possible effects of age, sex, sport, and upper and lower body weight training were investigated. The results in these young athletes showed that larger angles of thoracic kyphosis and lumbar lordosis were associated with greater cumulative training time. Gymnasts showed the largest curves. Lack of sports participation, on the other hand, was associated with the smallest curves. Age and sex did not appear to affect the degree of curvature.

Analysis and prevention of spinal column deformity following cervical laminectomy. I. Pathogenetic analysis of postlaminectomy deformities

Postlaminectomy deformities were simulated in the cervical or cervicothoracic spine by the use of a displacement incremental method based on finite-element analysis combined with composite material and spanning element theory. The simulation analyses revealed that the primary cause of postlaminectomy deformity was the resection of one or more spinous processes and/or posterior ligaments (ie, ligamenta flava, supraspinous, and interspinous ligaments). After their removal, the tensile stresses that were preoperatively distributed through the posterior ligaments were transferred to the facets. This led to an imbalance of the stresses on the spinal bodies, causing deformity. The gravitational center of the head determined whether the deformity would develop as a kyphosis or increasing lordosis. As the elastic modulus of the soft tissue composites (eg, end plates, ligaments, and facets) increased, a kyphotic deformity changed gradually from swan-neck deformity, to extreme kyphotic deformity with a large curvature, and finally to a straightening deformity. Progressive kyphotic deformity is found only in children.

Extensive simultaneous multisegment laminectomy for myelopathy due to the ossification of the posterior longitudinal ligament in the cervical region

Extensive simultaneous multisegment laminectomy (ESML) for treatment of ossification of the posterior longitudinal ligament (OPLL) in the cervical region is a technique which cuts the laminae on the median line and on the pedicles with an air drill, and then, the right and left halves of laminae are lifted simultaneously. This technique provides a protection to the spinal cord that swells instantaneously after decompression. A total of 155 cases were followed up for more than 1 year. According to the Japanese Orthopedic Association's evaluation criteria, 127 cases (81.9%) showed some improvement; specifically, 57 cases (36.8%) were rated excellent; 28 (18.1%), good; 42 (27.1%), fair; 11 (7.1%), unchanged; and 17 (11.0%) had poor results.

The effects of mammary hypertrophy on the skeletal system

Women with mammary hypertrophy usually have a number of complaints relating to the skeletal system. Neck strain, headache, aching shoulders, heavy anterior chest, and paresthesias of the little fingers disappear after reduction mammaplasty. Low back pain is either completely eliminated or dramatically improved. Posture may or may not be corrected. It is suggested that muscle reeducation be instituted in patients who do not show spontaneous improvement. Deep brassiere strap furrows may vanish after a long postoperative period, or they may be permanent. In any case, they become asymptomatic. The effects of hypertrophic breast on the skeletal system are many and varied. A few such problems are illustrated. Many more exist.

The impact of breast size on the vertebral column: a radiologic study

BACKGROUND

Macromastia usually is associated with the physical and psychological symptoms reported comprehensively by many studies. Reduction mammoplasty seems to be the most reasonable solution for these symptoms, and many articles have reported improvement of these complaints after surgery. Some authors have postulated that the anatomic mechanisms of postural aberrations are heavy breasts and related pain symptoms. However, limited numbers of studies have tried to explain the effect of the heavy breasts on the vertebral column.

METHODS

This study enrolled 100 females in four groups according to their breast cup sizes (groups A, B, C, D). All four groups were compared with each other statistically using one-way analysis of variance (ANOVA) followed by a post hoc test according to the body mass index (BMI) as well as the thoracic kyphosis, lumbar lordosis, and sacral inclination angles.

RESULTS

The BMI was significantly higher in the D cup-sized breast group. There was a statistically significant difference between groups A and D in terms of the thoracic kyphosis and the lumbar lordosis angles, and between groups B and D in terms of the lumbar lordosis angle. No statistically significant difference was detected between the groups in terms of the sacral inclination angle.

CONCLUSION

Breast size seems to be an important factor that affects posture, especially the thoracic kyphosis and lumbar lordosis angles.

Spinal deformity after multiple-level cervical laminectomy in children

Considerable controversy exists in the orthopedic and neurosurgical literature over the true incidence and nature of spinal deformity after multiple-level cervical laminectomy in children. Eighty-nine patients with a mean radiographic follow up of 5.1 years (range 2-9 years) were reviewed. Mean age at surgery was 5.7 years (range 1 month-18 years). Most common diagnoses were Arnold-Chiari malformation, syringomyelia, or both (81%). Significant deformity developed in 46 patients (53%), with 33 developing a mean kyphosis of 30 degrees (range 5-105 degrees) and 13 developing a mean hyperlordosis of 62 degrees (range 40-95 degrees). Peak age at surgery of 10.5 years correlated weakly (P = 0.08) with the development of kyphosis. The development of hyperlordosis was strongly correlated (P = 0.01) with a peak age at surgery of 4.2 years. There was no correlation between diagnosis, sex, location, or number of levels decompressed and the subsequent development of deformity.

Lordotic vertebrae in sea bass (Dicentrarchus labrax L.) are adapted to increased loads

Lordosis in fish is an abnormal ventral curvature of the vertebral column, accompanied by abnormal calcification of the afflicted vertebrae. Incidences of lordosis are a major problem in aquaculture and often correlate with increased swimming activity. To understand the biomechanical causes and consequences of lordosis, we mapped the morphological changes that occur in the vertebrae of European sea bass during their development from larva to juvenile. Our micro-CT analysis of lordotic and non-lordotic vertebrae revealed significant differences in their micro-architecture. Lordotic vertebrae have a larger bone volume, flattened dorsal zygapophyses and extra lateral ridges. They also have a larger second moment of area (both lateral and dorso-ventral) than non-lordotic vertebrae. This morphology suggests lordotic vertebrae to be adapted to an increased bending moment, caused by the axial musculature during increased swimming activity. We hypothesize the increase in swimming activity to have a two-fold effect in animals that become lordotic. The first effect is buckling failure of the axial skeleton due to an increased compressive load. The second effect is extra bone deposition as an adaptive response of the vertebrae at the cellular level, caused by an increased strain and strain rate in these vertebrae. Lordosis thus comprises both a buckling failure of the vertebral column and a molecular response that adapts the lordotic vertebrae to a new loading regime.

The natural history of scoliosis in myelodysplasia

Two hundred and fifty cases of myelodysplasia were reviewed in relation to spinal deformity. Approximately half of the children had, or were expected to develop, curves severe enough to need operations and only 10 per cent maintained completely undeformed spines. The most frequent deformity was scoliosis which could be subdivided into congenital and developmental types. The latter was of mixed aetiology, neuromuscular imbalance and asymmetry of the neural arch both contributing, while in some cases no causative factors could be identified. The best early indicator that developmental scoliosis was likely to appear was a high segmental level of both the neurological deficit and the neural arch defect. Deformity was very unlikely to start after the age of nine years.

Idiopathic scoliosis: the relation between the vertebral canal and the vertebral bodies

STUDY DESIGN

The axial length of the vertebral canal and the anterior aspect of the vertebrae were measured in 36 skeletons, 15 with probable idiopathic scoliosis.

OBJECTIVES

To compare the discrepancy in length of the vertebral canal and the anterior spinal column in skeletons having probable idiopathic scoliosis with the degree of deformity.

SUMMARY AND BACKGROUND DATA

In idiopathic scoliosis, the vertebral bodies rotate toward the convexity of the curve, whereas the vertebral canal tends to retain a midline position. The vertebral canal therefore will be relatively short. The degree of shortening has not been described previously, nor its relation with the degree of deformity.

METHODS

The axial length of the vertebral canal and the anterior aspect of the vertebral bodies were measured in 36 skeletons: 8 with normal spines, 13 with kyphosis, and 15 with probable idiopathic scoliosis. The relative shortening in the scoliotic spines was correlated with the Cobb angle and the degree of rotation.

RESULTS

No significant difference in length was found between the vertebral canal and the vertebral column in the normal spines. The kyphotic spines had canals significantly longer than the vertebral length (P<0.025). All but one of the scoliotic spines had short vertebral canals (P<0.01). The degree of discrepancy was related to the Cobb angle (r = -0.50; P< 0.05), and particularly to the degree of rotation (r = -0.88; P< 0.001).

CONCLUSIONS

The findings have surgical and etiologic implications. The results are consistent with a conceivable hypothesis that in some patients with idiopathic scoliosis, there may be impaired growth in the length of the spinal cord, the posterior elements are tethered, and as the vertebral bodies continue to grow, they become lordotic and then rotate.