Showing papers on "Cobb angle published in 1997"

Pedicle screw instrumentation of the thoracic spine in idiopathic scoliosis.

Abstract: Study design A prospective study of the accuracy of thoracic pedicle screw placement in patients with idiopathic scoliosis. Objectives To evaluate the accuracy of thoracic pedicle screw placement in the surgical management of idiopathic scoliosis and to establish its risks and benefits. Summary of background data Lumbar pedicle screw instrumentation has proven to be reliable and effective in the surgical management of scoliosis. No reports exist on the accuracy and benefits of pedicle screw instrumentation of the thoracic spine in scoliosis surgery. Methods One hundred and twenty thoracic pedicle screws in 32 consecutively treated patients with idiopathic scoliosis were investigated immediately after surgery by computed tomography scans that were analyzed by three examiners. Results Thirty (25%) of the screws penetrated the pedicle cortex or the vertebral body anterior cortex. Ten screws (8.3%) penetrated the medial cortex of the pedicle by an average of 1.5 mm and a maximum of 3.0 mm. Seventeen screws (14.2%) penetrated laterally by an average of 2.1 mm. There were two cases of caudad penetration. Three screws penetrated the anterior vertebral cortex, of which two also penetrated the pedicle cortex. Also, one of these three screws was replaced because of its direct proximity to the thoracic aorta. There were no neurologic complications. The correlation between the pedicle cortical penetration rate and the preoperative Cobb angle, vertebral rotation or level, or site of screw insertion was statistically insignificant (P > 0.05). Curve correction in the cases of mainly hook instrumentation averaged 52.5% versus 59.2% in the cases of mainly screw instrumentation. This difference was statistically insignificant (P > 0.05). Conclusions Pedicle or vertebral body cortical penetration occurred with 25% of the screws but with no neurologic compromise. Curve correction was slightly greater than with hooks, but not to a statistically significant extent.

Prediction of Correction of Scoliosis with Use of the Fulcrum Bending Radiograph

Abstract: We used a new method to assess spinal flexibility in thirty patients who were to be managed operatively for adolescent idiopathic scoliosis. The method involves placing the patient in the lateral decubitus position and bent over a fulcrum (a radiolucent padded cylinder) so that the spine is passively hinged open. For thoracic curves the fulcrum is centered under the rib corresponding to the apex of the curve, and for lumbar curves the fulcrum is placed directly under the apex. The preoperative workup for the thirty patients included an anteroposterior radiograph made with the patient standing, a lateral-bending radiograph made with the patient supine, and the new fulcrum bending radiograph. All patients were treated with posterior spinal arthrodesis with segmental spinal instrumentation. The degree of flexibility obtained with the traditional and new methods was compared with the degree of correction observed on the radiograph made, with the patient standing, one week after the operation. Preoperatively, the mean Cobb angle was 58 degrees on the anteroposterior radiograph made with the patient standing, 31 degrees on the lateral-bending radiograph made with the patient supine, and 24 degrees on the fulcrum bending radiograph. The mean angle was 25 degrees on the anteroposterior radiograph made one week postoperatively, so the mean correction was 57 per cent. The difference between the mean angle on the lateral-bending radiograph and that on the postoperative radiograph was significant (p < 0.001); however, the mean angle measured on the preoperative fulcrum bending radiograph and the postoperative angle were almost identical. We found the fulcrum bending radiograph to be more predictive of the degree of flexibility and correctability than the lateral-bending radiograph in this group of patients who had segmental spinal instrumentation for correction of idiopathic scoliosis.

Scoliosis and congenital anomalies associated with Klippel-Feil syndrome Types I-III

Abstract: Study design This investigation was aimed at characterizing anomalies and syndromes associated with Klippel-Feil syndrome in a large group of patients. The authors evaluated the clinical and radiographic features, documented the associated anomalies, and registered the type of treatment. Objective The anomalies or syndromes and the development of scoliosis were correlated to the type of Klippel-Feil syndrome. Material and methods In a cross-sectional study, the authors reviewed data from 57 patients with Klippel-Feil syndrome treated over 25 years at the Department for Orthopedics of the University of Heidelberg. The patients (17 males and 40 females; average age of the first contact, 12 years) were classified into three types according to the description of Feil in 1919. Results Klippel-Feil syndrome Type I (fusion of cervical and upper thoracic vertebra with synostosis) and Type II (isolated cervical spine) corresponded to 40% and 47% of patients, respectively. Type III (cervical vertebra associated with lower thoracic or upper lumbar fusion) was displayed in 13% of the patients only. The authors found a variety of combinations of Klippel-Feil syndrome and other anomalies in the patients examined in this study, with 67% of the patients characterized by an association with other disorders or syndromes. Of the patients, 70% showed scoliosis. Its degree depended on the type of Klippel-Feil syndrome. Scoliosis in Type I correlated with 31 degrees (Cobb angle), in Type III with 23 degrees, and in Type II with 9 degrees only. Thus, Type II, with isolated cervical fusion, shows a low risk for scoliosis. Conclusion This study increases knowledge of a wide range of anomalies and syndromes identified in association with Klippel-Feil syndrome. A special finding of the study was a correlation between the degree of scoliosis and Klippel-Feil syndrome Types I, II, and III.

Iliosacral screw fixation for pelvic obliquity in neuromuscular scoliosis. A long-term follow-up study.

Abstract: STUDY DESIGN This was a retrospective review of a consecutive series of patients with neuromuscular spinal deformity who underwent posterior fusion and pelvic fixation using a long construct and an iliosacral screw. OBJECTIVES To evaluate the risks and benefits of iliosacral screw fixation. SUMMARY OF BACKGROUND DATA Neuromuscular scoliosis with pelvic obliquity poses one of the most challenging instrumentation problems, mainly because of the poor bone quality frequently found within the sacrum. Complications include failure of instrumentation, loss of sacral fixation, loss of lumbar lordosis, and a high rate of nonunion. METHODS One hundred fifty-four patients with neuromuscular scoliosis and pelvic obliquity underwent posterior arthrodesis with pelvic fixation using an iliosacral screw. Anteroposterior scoliosis Cobb angle, frontal pelvic obliquity, and sacral inclination angle were measured before surgery, immediately after surgery, and at the 5-year and 3-month follow-up examination. Influence of etiology, severity of deformity, and associated anterior release at the scoliotic curve above also were assessed. RESULTS Correction of scoliosis Cobb angle ranged from 53% to 70%, and loss of correction ranged from 3% to 14% at the last follow-up examination. Correction of pelvic obliquity ranged from 60% to 84%, and loss of correction was mild. Sacral inclination angle approached normal values in all patients, except for those with myelomeningocele who had preoperative pelvic retroversion. Loss of correction ranged from 0.3 degree to 5.4 degrees at the last follow-up examination. Complications and loss of correction mostly were encountered in patients with myelomeningocele and spinal muscular atrophy. CONCLUSIONS Iliosacral screw fixation in neuromuscular scoliosis is technically standardized and easy and offers mechanically efficient and stable fixation.

Early detection of progression in adolescent idiopathic scoliosis by measurement of changes in back shape with the Integrated Shape Imaging System scanner.

Abstract: STUDY DESIGN A retrospective study of 78 patients with right thoracic idiopathic scoliosis was done. OBJECTIVES To evaluate the reliability of the integrated Shape Imaging System scan (Oxford Metrics Ltd, Oxford, UK) in detecting progression of scoliosis and the use of back shape data in predicting scoliosis progression. SUMMARY OF BACKGROUND DATA At first presentation and every 3-6 months during the follow-up period, all patients underwent integrated Shape Imaging System scans and radiographic examinations, from which the Cobb angle was measured. The follow-up period was 18-49 months (mean = 31.4 months). METHODS Patients were divided into three groups according to the severity and progression of the Cobb angle. The spinal fusion, brace, and observation groups were compared using analysis of variance and the student's t test to detect significant differences among groups in the progression of deformity as measured by the integrated Shape Imaging System parameters and the Cobb angle. RESULTS Three of the Integrated Shape Imaging System parameters detected significant progression in the spinal fusion group 1 year earlier than the Cobb angle. Only one of the Integrated Shape Imaging System parameters detected a significant difference in progression between the brace and observation groups. CONCLUSIONS The Integrated Shape Imaging System technique demonstrated significant changes in this group of patients with progressive scoliosis. Serial measurements of back surface shape, particularly the size of the rib hump, may be predictive of progression. Serial Integrated Shape Imaging System scanning has advantages over serial radiography in the management of idiopathic scoliosis in addition to the avoidance of exposure to ionizing radiation.

Cut-off point of the Scoliometer in school scoliosis screening

Abstract: Study design A large-scale study on school screening for scoliosis was conducted to assess the referral rate, prevalence rate, and positive predictive value using different angles of trunk rotation as criteria for referral. Objective To determine an ideal angle of trunk rotation cut-off point to be used for referral in school screening for scoliosis. Summary of background data When using the Scoliometer (Orthopedic Systems, Inc., Hayward, CA) in school scoliosis screening, 5 degrees and 7 degrees angles of trunk rotation have been recommended as criteria for referral. Low positive predictive values and over-referral at these levels have been reported. Methods The Adams forward bend test and Scoliometer measurement were combined for school scoliosis screening in 33,596 girls from the fifth, sixth and seventh grades. Nurses were the primary screeners. Girls with trunk rotation angles of 5 degrees or more were referred for radiography. Results The referral rate was 5.2%. By selecting 6 degrees, 7 degrees, 8 degrees, 9 degrees or 10 degrees angles of trunk rotation as criteria for referral, the referral rate became 2.4%, 1.4%, 0.7%, 0.5%, or 0.3%, respectively. The prevalence rate for scoliosis equal to or larger than 10 degrees, 20 degrees, 30 degrees, or 40 degrees of the Cobb angle was 1.47%, 0.21%, 0.04% and 0.02%, respectively, by using a 5 degrees angle of trunk rotation as the criterion for radiography. The positive predictive value was 28.3% for scoliosis of 10 degrees or more, 4% for scoliosis of 20 degrees or more, 0.8% for scoliosis of 30 degrees or more, and 0.4% for scoliosis of 40 degrees or more with a 5 degrees angle of trunk rotation as the criterion for referral. By selecting angles of trunk rotation larger than 5 degrees as criteria for referral for radiography, the positive predictive value increased, but positive cases with larger Cobb angles also decreased markedly. Conclusion The optimal cut-off point for referral when using the Scoliometer in school screening of scoliosis is still difficult to determine.

Scoliosis and developmental theory: adolescent idiopathic scoliosis.

Abstract: STUDY DESIGN Statistical analysis of maturity and asymmetry criteria in adolescent idiopathic scoliosis. OBJECTIVES To explore the hypothesis that scoliosis is a manifestation of developmental destabilization under physiologic stress. BACKGROUND Advances in genetics and theoretical biology have broadened the understanding of morphogenesis and the controlling mechanisms for the development of the adult form. The morphologic genome can be viewed as a cybernetic control system, and the homeobox genes can be viewed as the master controls for the specific subroutines. Deformity will occur from a faulty "program" or a disturbance in the running of that program. An early and subtle indication of such an occurrence is failure of bilateral symmetry. METHODS An analysis of variance in Cobb angle, age at diagnosis, and apical site in 327 girls with spinal curves 5 degrees or greater according to prospectively maintained scoliosis screening records was performed. Dermatoglyphics were compared in 114 female control individuals and 164 female patients with adolescent idiopathic scoliosis (minimum Cobb angle, 10 degrees), and then by subdivision into school screening (n = 86) and general clinic referrals (n = 78). RESULTS Girls from the screening program (from the years 1979-1990) had statistically significant associations between age and apical vertebra, suggesting an age-deformity relationship independent of maturation and growth spurt. Girls with adolescent idiopathic scoliosis from a later cohort, both screened and unscreened, had increased directional asymmetry, as previously reported. There was a statistically significant increase in fluctuating asymmetry in general clinic referrals when compared with school screening referrals. CONCLUSIONS Developmental instability can explain adolescent idiopathic scoliosis as part of wider developmental theory without the necessity of a disease process in the etiology. The differences between screening and general clinic referrals suggest the need for natural history studies, and treatment protocols also should consider the provenance of the individuals described.

The crankshaft phenomenon after posterior Harrington fusion in skeletally immature patients with thoracic or thoracolumbar idiopathic scoliosis followed to maturity.

Abstract: Study design This retrospective study evaluated the progression of deformity after posterior fusion by reviewing 63 consecutive patients with idiopathic scoliosis who were all in Risser sign 0 at the time of surgery. All patients were observed beyond the time of skeletal maturity. Average follow-up time was 9 years and 8 months (range, 5-16 years). Objectives To investigate the risk factors for the crankshaft phenomenon after posterior fusion and to build a model for predicting the probability of curve progression until maturation of growth. Summary of background data There remains considerable controversy concerning the incidence, risk factors, and necessity of combined anterior fusion to prevent the crankshaft phenomenon in patients who are skeletally immature. Methods Serial radiographs were measured for Cobb angle, apical rotation according to Perdriolle, and apical rib-vertebra angle of Mehta. Multivariate and univariate logistic regression analysis was performed using seven potential predictors as independent variables and Cobb angle progression and rotational progression as dependent variables. Results Average progression of deformity was 3 degrees Cobb angle (range, -8-16 degrees) and 3 degrees Perdriolle rotation (range, -9-17 degrees). Progression of deformity more than 5 degrees of either Cobb angle or rotation was observed in 22 (35%) of 63 curves with 7 (11%) of 63 curves greater than 10 degrees. Chronologic age and skeletal age were found to be significantly associated with progression of deformity in univariate analysis. In multivariate analysis, only skeletal age seemed to be independently prognostic. The authors tried to build the logistic model using the three factors of chronologic age, skeletal age, and apical rib-vertebra angle. This model correctly classified 81% of all patients as progressive or nonprogressive. The positive predictive value was 90%. Conclusions The results showed that patients with chronologic age of 11 years of younger, especially those with a skeletal age of 10 years or younger, had a high estimated probability of progression of deformity. The progression was fairly moderate, however, with an average Cobb angle of 9 degrees and average rotation of 7 degrees, which neither the patients nor the surgeon believed was of such magnitude as to warrant routine combined anterior fusion.

The role of preoperative pulmonary function tests in patients with adolescent idiopathic scoliosis undergoing posterior spinal fusion.

Abstract: Study design A retrospective review of the case records and radiographs of 133 patients with adolescent idiopathic scoliosis who underwent posterior spinal fusion and instrumentation between 1986 and 1992. Objectives To evaluate the incidence of abnormal results on preoperative pulmonary function tests and their correlation to immediate postoperative pulmonary impairment in patients with adolescent idiopathic scoliosis who had posterior spinal fusion. Summary of background data It has been stated that preoperative pulmonary function tests are essential to assess surgical risk in a patient with scoliosis because of the possibility of further compromising the pulmonary function. Authors of previous studies have reported on the increased incidence of postoperative pulmonary complications in patients undergoing anterior spinal surgery. Methods The case records and radiographs of 133 patients with either a thoracic or a double-major curve, who underwent posterior spinal fusion, were reviewed. The presence of any preoperative or postoperative cardiopulmonary symptoms and increased requirement of postoperative ventilatory support were noted. Results of preoperative pulmonary function tests were classified as normal, restrictive, or obstructive disease. Postoperative chest radiographs were examined to note the presence of atelectasis, infiltrates, pneumothorax, hemothorax, or pneumonia. Results The majority of patients (72.9%) had normal results on pulmonary function tests. The mean coronal Cobb angle of the thoracic curve was 48 degrees, and the mean angle of kyphosis was 26 degrees. None of the patients had any increased requirement of postoperative ventilatory support. The overall incidence of postoperative pulmonary complications was 2.3%. Conclusions Performance of a thoracoplasty was the only risk factor for postoperative pulmonary complications in patients undergoing posterior spinal fusion. There was no correlation between deterioration of preoperative pulmonary function and the risk of postoperative pulmonary complications. It appears that performance of preoperative pulmonary function tests in patients with moderate adolescent idiopathic scoliosis-scheduled for posterior spinal fusion is not necessary.

Analysis of symmetry of vertebral body loading consequent to lateral spinal curvature.

Abstract: STUDY DESIGN A biomechanical model was used to calculate muscle and intervertebral forces in a spine with and without a lumbar scoliosis. OBJECTIVES To quantify the loading of the motion segments in a lumbar scoliosis. SUMMARY OF BACKGROUND INFORMATION Scoliosis is thought to cause asymmetric loading of vertebral physes, causing asymmetric growth according to the Hueter-Volkmann principle. The magnitude of vertebral loading asymmetry as a function of scoliosis magnitude is unknown, however, as is the sensitivity of growth to asymmetric loading. METHODS The analysis included five lumbar vertebrae, the thorax, and the sacrum/pelvis and 90 pairs of multijoint muscles. Five spinal geometries were analyzed: the mean spinal shape of 15 patients with left lumbar scoliosis (38 degrees Cobb angle, apex at L1-L2, the reference or "100%" geometry), and the geometry scaled to 0%, 33%, 67%, and 132% of the asymmetry of the reference shape. The muscle and intervertebral forces for maximum efforts opposing moments applied to the T12 vertebra in each of the three principal directions were calculated. The loading at each intervertebral level was expressed as the resultant force (P), the axial torque, the lateral and anteroposterior offset of P from the disc center, and the angle of P from the axial direction. RESULTS With increasing scoliosis, there was a weak trend of increasing lateral offset of P, but not consistently to either the convex or concave direction. There was a much stronger trend of increasing angle between the force P and the motion segment longitudinal axis with increasing Cobb angle. Typically, this angle was 10-30 degrees for the largest scoliosis (51 degrees Cobb) and in a direction tending to increase the scoliosis. This angulation of the force results from shear loading of the disc. Axial torques tending to increase the transverse plane deformity increased with scoliosis for extension efforts. CONCLUSIONS These analyses indicate that lumbar scoliosis produces asymmetric spinal loading characterized by shear forces tending to increase the scoliosis, but with little increase in the asymmetric compression of motion segments. If scoliosis progression results from asymmetric loading, it appears that the shear force component is responsible.

Trunk rotation in scoliosis the influence of curve type and direction in 150 children

Abstract: We compared the angle of trunk rotation (ATR) from scoliometer readings with Cobb angle measurements of the lateral deviation of the spine in 150 children referred to hospital for evaluation of scoliosis. the mean Cobb angle in thoracic curves was 16 °, in thoracolumbar curves 17° and in lumbar curves 20°. in thoracic curves and in right convex curves no patient with a Cobb angle of 25° or more had an ATR below 9°. in thoracolumbar and lumbar and in left convex curves, 7° ATR was occasionally associated with scoliosis of 25° or more. the correlation coefficient between the ATR and Cobb angle in right convex curves was 0.65 compared to 0.57 in left convex curves. We conclude that a criterion of 7° ATR for thoracic or right convex curves and one of 6° ATR for thoracolumbar and lumbar or left convex curves seem adequate for identification of patients with Cobb angles of 25° or more, which reduces the need for spinal radiography and follow-up outside the school screening programs.

Interpretation and utility of traction radiography in scoliosis surgery. Analysis of patients treated with Cotrel-Dubousset instrumentation.

Abstract: STUDY DESIGN An analysis of a standardized method of traction radiography for the evaluation of reducibility of scoliosis. OBJECTIVES To determine whether and how preoperative fraction radiography can provide objective information and to compare traction radiography with supine side-bending radiography. SUMMARY OF BACKGROUND DATA Flexibility of scoliosis deformity remains an arbitrary concept. No objective method of preoperative evaluation of reducibility has been established. METHODS The utility of a standardized method of traction radiography was evaluated in 74 patients with idiopathic scoliosis who were aged 14-22 years and treated with Cotrel-Dubousset instrumentation. RESULTS In thoracic curves, the postoperative Cobb angle was highly correlated with the preoperative Cobb angle in traction (r = 0.82). However, such correlation was much lower with lumbar curves (r = 0.54). The reducibility of the thoracic curve by traction as expressed by the ratio to the original curve was dependent on the magnitude of the original curve (P = 0.005), and this parameter proved less informative than the absolute angle values. Time-related analysis of 30 patients who were observed for more than 5 years revealed that the high correlation between the preoperative angle of thoracic curves in traction and their postoperative angle decreased with the follow-up time (r = 0.80-0.65). A comparison of traction radiography and supine side-bending radiography showed that these two tests were practically equivalent in terms of evaluating the reducibility of curves. CONCLUSION The results provide an objective interpretation of traction radiographs for scoliosis.

Rib-vertebral angle asymmetry in idiopathic, neuromuscular and experimentally induced scoliosis

Abstract: The concave and convex rib-vertebral angle (RVA) at levels T2–T12 was measured on AP radiographs of 19 patients with right convex idiopathic thoracic scoliosis and 10 patients with major thoracic right convex neuromuscular scoliosis. The difference between the angles on the concave and the convex sides, the RVAD, was calculated. The RVAs were also measured on radiographs from three animal groups in which spinal curves had been induced experimentally in a variety of ways. Group 1 comprised 16 rabbits that had been subjected to selective electrostimulation of the latissimus dorsi, the erector spinae and the intercostal muscles. Group 2 comprised four dead rabbits whose spines had been subjected to manual bending. Group 3 comprised eight rabbits that had undergone mechanical elongation of one rib. In both the idiopathic and the neuromuscular group, the convex RVA was smaller than the concave RVA between levels T2 and T8, with a maximal difference between T4 to T5. From T9 to T12 the concave RVA was smaller than the convex. The RVA in relation to the scoliotic segment, i.e. the apex level of the curve and the two neighbouring vertebrae above and below this level, showed similar results. With increasing Cobb angle the RVADs increased linearly with the greatest difference at the second vertebra above the apex. In the three experimental groups the pattern of the RVADs between T6 to T12 was basically similar to the findings of the clinical study. From the results of these clinical and experimental studies, it is concluded that the typical pattern of the RVAs on the concave and convex sides seems to be independent of the underlying cause of the spinal curvature. It is likely that the RVADs result from a passive mechanical adaptation of the ribs to the lateral curvature of the spine.

Anterior instrumentation in idiopathic scoliosis: a minimum follow-up of 10 years

Abstract: One hundred and thirty-four patients with idiopathic scoliosis were treated between 1973 and 1993 in our hospital, and 53 were followed for a minimum of 10 years in a retrospective study. Forty-five were female and 8 male with an average age of 32 years at follow up. Dwyer instrumentation was used in 17 and Zielke in 36. The curve was thoracic in 16, thoracolumbar in 27 and lumbar in 10. The average preoperative Cobb angle was 64 degrees. The average angle at follow up was 21 degrees with 62% of the average correction maintained (61% in the Dwyer and 65% in the Zielke). Most patients were satisfied subjectively and we recommend this type of operation.

A new technique for the three-dimensional study of the spine in vitro and in vivo by using a motion-analysis system.

Abstract: We introduce a new method with a motion-analysis system (MAS) to study the vertebral model in vitro. Compared with the currently most accurate technique, roentgen stereophotogrammetric analysis (RSA), the difference between the RSA and the MAS is 0.12 degree +/- 1.64 degrees. An accuracy with an error of 0.08 degree +/- 1.15 degrees is determined by means of an angle gauge. Although a significant difference between the MAS and the goniometer (p = 0.04) is found around the X-axis (theta; transverse plane), it is limited to < 1 degree. The MAS provides an in-depth insight into the mechanism of the three-dimensional rotation at each vertebra in vivo. The backward inclination of the apical vertebra (AV) and forward inclination of the upper-end vertebra (UEV) around the Y-axis (phi) results in a correction of the hypokyphosis shown by the Cobb angle in the sagittal plane. The clockwise rotation of the UEV in the Z-axis (psi) leads to a reduction of the Cobb angle in the frontal plane. Additionally, the MAS as an intraoperative alternative shows different results of the derotation maneuver by the Cotrel-Dubousset instrumentation (CDI) compared with the computed tomography (CT) scan. Our method gives more direct details of the derotation not influenced by patient posture, as observed in the CT scan.

[Monosegmental internal fixator instrumentation and fusion in treatment of fractures of the thoracolumbar spine. Indications, technique and results].

Abstract: Dorsal fusion with the internal fixator has become the standard treatment of instabilities and deformities of the thoracolumbar spine. With our new device, the modular spine fixator (MSF), which has been specially designed for short-distance instrumentations, we have increasingly been treating unstable injuries of the thoracolumbar spine by one-level stabilization. Prerequisite is an accurate evaluation of the indication, including CT and MRI to assess the involvement of the intervertebral disc and the ligamental structures. The operative technique differs in some details from the procedure in moremulti-level instrumentations, especially concerning the application of the pedicle screws. The instrumentation is always combined with posterior allogenic bone grafting. Since the beginning of 1993 we also perform anterior autogenic transpedicular bone grafting. Between Januar 1991 and July 1995, 57 one-level stabilizations with the MSF were performed. Of the 57 patients operated on 39, 27 men and 12 women, with an average age of 41 years, have had a clinical and radiographic follow-up examination so far, on average, 27 months after the accident. Seventeen patients were completely free of pain and 17 patients (were only) sensivite to weather changes or had minor pain during great physical stress. Five patients had pain even during slight physical stress or at rest. The preoperatively measured Cobb angle was 15.1 ° on average, after the operation 5.2 °, and at the time of the follow-up examination amounted to 8.1 °. The patients' range of motion was normal. Only five minor complications have been seen. No implant fatigue failure has been noted in this series. We derive from these results that, for correct indications, one-level stabilization can be performed successfully and should be firmly established in the operative treatment of unstable fractures of the thoracolumbar spine.

Indications for surgery in so-called "regular" thoracic and thoracolumbar kyphosis.

Abstract: Idiopathic thoracic, thoracolumbar, and Scheuermann's kyphosis do not figure in the same global entity. We propose a classification for so-called “regular” kyphosis. This classification is based on the location of the most rigid curvature segment. Segmental kyphosis may be short, in which case we can distinguish between four types: high kyphosis (type I), middle kyphosis (type II), low or thoracolumbar kyphosis (type III), and segmental kyphosis, which can extend along the entire thoracic spine (type IV). The symptomatology and therapeutic indications are different for each type. We report a series of 15 patients (6 female, 9 male), aged between 18 and 33 years (average age 24 years). The mean kyphosis angle (Cobb angle) in type I patients (n = 3) was 75° in type II patients (n = 3) it was 82°, and in type III patients (n = 9) it was 78°. The pain was greater in type III patients. All patients were operated on using a double approach. As the first step, we performed an anterior approach, disc excision, and bone graft. Ten days later, a posterior approach with CD instrumentation was carried out on ten levels. The mean follow-up is 4 years (range 9 months in 7 years). We noticed no neurological complications and one case of late sepsis. Mean angular loss of correction was 6°. The correction obtained dependend on the type of kyphosis. We obtained a mean postoperative Cobb angle of 63° in type I curves, 55° in type II, and 45° in type III. The new classification allows a better understanding of regular kyphosis and helps to define clinical and therapeutic approaches. An analysis of the resulting surgical correction can also be made by comparing homogeneous groups of patients.

Correction of experimental scoliosis by rib resection in the transverse plane.

Abstract: Experimental scoliosis with the potential for marked progression was treated by rib resection on the concave side of the curve, and the alterations of the rib cage and vertebrae in the transverse plane were investigated. Twenty-four chickens were divided into four equal groups (groups R, P, PR, and C) and pinealectomy was performed at 3 days of age in groups P and PR. In group R, three unilateral ribs were resected at the age of 4 weeks. In group PR, three ribs on the concave side of scoliosis were resected at 4 weeks of age if scoliosis of > 20 degrees developed before the age of 4 weeks. Group C served as a control. Spinal radiographs and computed tomography scans at the apical vertebrae were taken at 20 weeks of age, and spinal deformities were evaluated. Scoliosis developed markedly in groups R and P, whereas it was mild in group PR. The apical vertebrae rotated to the convex side of the curve in all groups, in the same way as it would in human idiopathic scoliosis. In group PR, the Cobb angle and the rotation angle of the apical vertebra were symmetrically suppressed. This study indicated that rib resection might control the progression of scoliosis not only in the frontal plane but also in the axial plane when it was done on the concave side of the scoliosis. Although this experiment succeeded in chickens, application in humans is uncertain.

The effects of spinal fusion on respiratory function and quality of life in Duchenne muscular dystrophy

Abstract: We studied the functional outcome of spinal fusion for the surgical treatment of scoliosis in 8 patients with Duchenne muscular dystrophy (DMD). The mean age of DMD patients at the time of the surgery and the mean follow-up duration was 13.8 (12.3 to 15.4) and 3.9 (1.5 to 6.8) years, respectively. The average spinal angle (Cobb angle) was corrected from 58.8 to 28.6 degrees with the mean corrective rate of 51.3% by the surgical intervention. The correction rate was higher and the corrected Cobb angle remained unchanged during follow-up period in mildly scoliotic patients. Forced vital capacity (FVC) increased post-operatively in 3 patients with moderate scoliosis (Cobb angle: 50 to 80 degrees), indicating that the correction of spinal alignment is effective for the treatment of decreased thoracic volume in DMD. On the other hand, two cases with low % FVC (16.9% and 30.4%, respectively) had poor prognosis in respiratory status. Namely, one died of pneumonia at 17 months after the surgery and the other required mechanical ventilation via nasal mask at 3 years post surgery. Sitting balance improved in all patients, which resulted in more functional use of their upper extremities. During the follow-up period, all patients except one patient who died of pneumonia could maintain sitting balance without support. Moreover these included 2 patients over 20 year old. No complications related to spinal deformities have been found in these patients. Previous study in our hospital showed that 7 of 48 (14.6%) of DMD patients spent all their lives without apparent scoliosis (Cobb angle less than 30 degrees). These suggest that spinal fusion could be recommended for patients with Cobb angle more than 30 degrees and with % FVC more than 35%. Although the impact of spinal fusion upon the life expectancy remains unclear, favorable effect on respiratory function and quality of life can be expected for carefully selected patients with DMD.

Application of tuberculosis medical examination radiographs to scoliosis screening in high schools

Abstract: The purpose of this study was to assess the utilization of tuberculosis examination radiographs for scoliosis screening in high schools, for early diagnosis and early treatment of adolescent idiopathic scoliosis in the health management of students. We examined 2,068 first year high school students (1,058 males and 1,010 females) in Wakayama Prefecture, who had chest X-ray photographs taken between 1994 to 1996, and 24 cases (3 males and 21 females) were identified with scoliosis of more than 10 degrees Cobb angle. Fifteen of the cases received further examinations in the hospital, and were diagnosed with definite adolescent idiopathic scoliosis, while 6 cases who did not receive hospital examinations had their abnormality of the spine noted in past periodic health examinations. In the remaining 3 students scoliosis could not be confirmed. The correlation coefficient between the Cobb angle measured in the tuberculosis examination radiographs and in the total spinal radiographs taken by the hospital was 0.815 (p < 0.001). These results suggest that the tuberculosis examination radiographs may be useful for scoliosis screening in high schools.

Surgical treatment of idiopathic scoliosis with multisegmental posterior instrumentation and its influence on postoperative spinal balance

Abstract: Causes of postoperative spinal imbalance in patients with idiopathic scoliosis treated with multisegmental posterior instrumentation CD or TSRH and posterior fusion are presented. Investigation included 88 patients (77 girls, 11 boys) aged 11.4-17.1 (mean 13.8). Primary curve Cobb angle ranged from 52 (to 133 mean 75), secondary curve 16 (to 88 mean 47). Follow-up ranged from 12 to 19 months (mean 18.2 months). In 31 patients (35.2%) postoperative decompensation of the spine occurred. Six of them regained spinal balance within 12 to 19 months postoperatively. As the magnitude of correction increased in relation to preoperative correctiveness and/or preoperative rotation of the spine the imbalance of the spine was more pronounced. It was worsened also in cases where spontaneous correction within the secondary curve (not instrumented) was lesser than expected. Thoracic curve overcorrection in type II scoliosis with instrumentation inclusive of 1 or 2 vertebrae beyond neutral one resulted in decompensation to the left. To short a fusion (in relation to neutral and stable vertebrae) caused in this type as well as in type II and IV right sided decompensation. Overcorrection of lower (right sided) curve or omission of upper (left sided) curve in type V scoliosis caused shoulder girdle decompensation. In type I lumbar fusion done proximally to neutral and stable vertebrae caused left side decompensation of the spine.