Correction Of Scoliotic Deformity Research Articles

A three-dimensional retrospective analysis of the evolution of spinal instrumentation for the correction of adolescent idiopathic scoliosis

This is a clinical radiographic study, spanning over three decades, analyzing the three-dimensional (3-D) changes in spine geometry after corrective surgery for adolescent idiopathic scoliosis (AIS) using four generations of instrumentation systems. The objective of this study was to retrospectively evaluate the evolution of spinal instrumentation over time by measuring the 3-D changes of spinal shape before and after surgical correction of subjects with AIS using Harrington/Harrington-Luque (H/HL) instrumentation, original and recent generations of Cotrel-Dubousset Instrumentation (CDI) with rod rotation maneuvers, as well as third generation systems using thoracic pedicle screws and direct vertebral derotation (DVD) manoeuver in order to determine if the claims for improved 3-D correction from generation to next generation could be substantiated. The 3-D shape of the thoracic and lumbar spine was recorded from a pair of standing radiographs using a novel 3-D reconstruction technique from uncalibrated radiographs in 128 adolescents with AIS undergoing surgery by a posterior approach. Changes in coronal Cobb angles, kyphosis, lordosis, as well as in a series of 3-D parameters computed from the spine reconstructions before and after surgery were used to compare the four groups. Results demonstrate statistically significant differences (P = 0.05) between generations with regards to the correction of the coronal Cobb angle, and different loss of physiological lordosis. More importantly, significant differences in the 3-D correction of the spine based on the orientation of the planes of maximal curvature were observed (20/-6% H/HL vs. 39/39% CDI vs. 42/18% DVD for the thoracic/lumbar regions, respectively), confirming that recent CDI and third generation instrumentations coupled with DVD can bring the deformity significantly closer to the sagittal plane. An increased correction in apical vertebra axial rotation was observed with the DVD manoeuver (74%), while fewer notable differences were found between DVD and recent CDI systems in terms of 3-D correction. This is the first quantitative study to clearly demonstrate that the rod derotation and DVD maneuvers can significantly improve 3-D correction of scoliotic deformities, thereby supporting the transition towards these more elaborate and costly instrumentation technologies in terms of 3-D assessment.

Preoperative Planning Simulator for Spinal Deformity Surgeries

Proof of concept of a spine surgery simulator (S3) for the assessment of scoliosis instrumentation configuration strategies. To develop and assess a surgeon-friendly spine surgery simulator that predicts the correction of a scoliotic spine as a function of the patient characteristics and instrumentation variables. There is currently no clinical tool sufficiently user-friendly, reliable and refined for the preoperative planning and prediction of correction using different instrumentation configurations. A kinetic model using flexible mechanisms has been developed to represent patient-specific spine geometry and flexibility, and to simulate individual substeps of correction with an instrumentation system. The surgeon-friendly simulator interface allows interactive specification of the instrumentation components, surgical correction maneuvers and display of simulation results. The simulations of spinal instrumentation procedures of 10 scoliotic cases agreed well with postoperative results and the expected behavior of the instrumented spine (average Cobb angle differences of 3.5 degrees to 4.6 degrees in the frontal plane and of 3.6 degrees to 4.7 degrees in the sagittal plane). Forces generated at the implant-vertebra link were mostly below reported pull-out values, with more important values at the extremities of the instrumentation. The spine surgery simulator S3 has proven its technical feasibility and clinical relevance to assist in the preoperative planning of instrumentation strategies for the correction of scoliotic deformities.

Segmental Pedicle Screwing for Idiopathic Scoliosis Using Computer-assisted Surgery

Retrospective clinical study. To evaluate the accuracy of computer-assisted surgery for idiopathic scoliosis. Segmental pedicle screw fixation has been proven to enable enhanced correction of scoliotic deformities. However, both neurovascular and visceral structures are at potential risk from screw misplacement due to pedicle drift. No reports exist on the accuracy and benefits of computer-assisted surgery for pedicle screwing in scoliosis surgery. A total of 40 consecutive patients with idiopathic scoliosis were evaluated. Postoperative computed tomography was assessed for the accuracy of pedicle screw placement in 20 cases treated without a navigation system and 20 cases with a computed tomography-based navigation system. Correlations between registered levels and pedicle perforation were investigated. Pedicle violation was observed in 28.0% of the control group and 11.4% of the navigation group, with significant differences. No screw misplacements at the registered levels were seen, and the longer the distance between the registered level and level of screw insertion, the higher the rate of pedicle violation. No intraoperative complications caused by pedicle perforation occurred. In the navigation group, a tendency to lateral perforation at the concave side and medial perforation at the convex side was noted, like in the control group. Use of the navigation system significantly reduced the screw misplacement rate for rotated vertebrae as compared with the control group. Separate registration is recommended for rotated vertebrae when possible.

Does Obesity Affect Surgical Outcomes in Adolescent Idiopathic Scoliosis?

A retrospective review of surgical outcomes in adolescents with idiopathic scoliosis. To determine if an association exists between body mass and surgical outcomes in adolescent idiopathic scoliosis (AIS). Obesity has reached epidemic proportions globally. In adults, obesity increases the likelihood of developing multiple medical comorbidities and has been associated with an increased incidence of perioperative complications. The effect of obesity on surgical outcomes in the treatment of AIS patients has not been studied previously. Radiographic measures, perioperative data, and Scoliosis Research Society Outcomes scores were collected on surgically treated AIS patients. The body mass index (BMI) was calculated for each patient and normalized to sex and age (BMI %). Analysis of variance was used to identify differences between healthy weight (BMI % <85) and overweight patients (BMI % >or=85). The data were checked for normality and equal variances, and the level of significance was set at 0.01. Two hundred forty-one patients (204 women, 37 men; 14.3 +/- 2.0 years) with a minimum of 2-year follow-up met the inclusion criteria for this study. The average BMI (kg/m2) was 20.7 +/- 3.7 (BMI % average: 54.5, range: 1-99). No significant differences were found between the overweight (n = 48) and healthy weight (n = 193) patients with regards to surgical time, estimated blood loss, major Cobb percent correction, maintenance of correction, rate of implant failure, pseudarthrosis, and surgical revision. However, the preoperative thoracic kyphosis was significantly greater in the overweight group (27.0 degrees +/- 12.6 degrees) compared with the healthy weight patients (21.8 degrees +/- 12.5 degrees) (P = 0.004). Overweight adolescents (BMI % >or=85) had a greater thoracic kyphosis before surgery compared with their healthy weight peers. Body mass, however, did not affect the ability to achieve coronal or sagittal scoliotic deformity correction, and did not increase perioperative morbidity or mortality. These findings were either influenced by the small sample size of this cohort, or because the comorbidities responsible for increased perioperative complications in adults, had not yet developed in this adolescent population.

Virtual prototyping of a brace design for the correction of scoliotic deformities

Based on a three-dimensional patient-specific finite element model of the spine, rib cage, pelvis and abdomen, a parametric model of a thoraco-lumbo-sacral orthosis (TLSO) was built. Its geometry is custom-fit to the patient. The rigid shell, pads and openings are all represented. The interaction between the trunk and the brace is modeled by a point-to-surface contact interface. During the nonlinear simulation process, the brace is opened, positioned on the patient and strap tension is applied. A TLSO similar to Boston brace system was built for a right-thoracic scoliotic patient. The influences of the trochanter pad and strap tension on the 3-D geometrical corrections and on the forces generated by the brace were evaluated. The role of the trochanter pad as a lever arm is confirmed by the model. The brace induces a reduction of the lordosis and pelvic tilt. The reduction of the frontal curvature is about 20% for a strap tension of 60 N. Axial rotation does not significantly change and rib hump is worsened. By using an explicit brace model and a contact interface, a more realistic simulation of orthotic treatment of scoliosis can be achieved. The stabilization of the brace on the patient can be represented and less restrictive boundary conditions can be applied. This model could be used to study the effect of design parameters on the brace efficiency.

CORRECTION AND STABILIZATION OF THE SPINE WITH NEW GENERATION IMPLANTS FOR VERTEBRAL CONGENITAL MALFORMATIONS IN CHILDREN AGED ONE TO FIVE YEARS

Objectives. To analyze the results of correction and stabilization of the spine with new generation implants for congenital malformation of the vertebrae in children of 1 to 5 years old. Material and Methods. A metal construction for surgical treatment of congenital anomalies of the spine in children of 1 to 5 years old was developed, consisting of transpedicular and laminar support elements. This construction was used in 38 patients with congenital thoracic and lumbar spine deformities associated with malformations of the vertebral bodies. Six patients had an isolated lateral or posterior-lateral hemivertebra in the thoracic spine and 11 – in the thoracolumbar junction, 3 patients had wedge-shaped vertebra in the thoracolumbar spine, and 18 – multiple or combined developmental anomalies of the spine. Initial angulation of scoliotic deformity was 24° to 50° and kyphotic deformity – 20° to 46°. Surgical treatment consisted of one-moment three-staged operation according to developed technique. Results. Correction of deformity within 92–100 % was achieved in patients with isolated hemivertebra in the thoracic and lumbar spine, and posterior wedge-shaped vertebrae in the thoracolumbar junction. In patients with multiple and combined developmental anomalies of the spine the correction of scoliotic deformity was 52–76 % and of kyphotic one – 58–80 %. Conclusion. The suggested metal construction provides the possibility to perform surgery at early stages even for developmental anomalies of the spine posterior support column in patients of 1 to 5 years old with congenital spine deformities.

TREATMENT OF PATIENTS WITH GRADE III–IV THORACOLUMBAR SCOLIOSIS AFTER PRIOR SURGERY BY HARRINGTON METHOD

Objective. To analyze the results of idiopathic scoliosis correction with instrumentation developed by the authors in patients previously operated by the Harrington method. Material and Methods. Ten patients of 14–31 years of age with grade III–IV scoliotic deformity previously operated by the Harrington method were reoperated with universal endocorrector. The reasons for repeat surgery included a fracture of Harrington rod, insufficient correction of scoliotic deformity, perforation of the vertebral arch by distractor hook, and the trunk imbalance. All patients underwent simultaneous two-stage surgery involving distractor removal and scoliosis correction with universal endocorrector. The follow-up period was 6–24 months. Results. Mean correction in rod fracture group was 61.08 % without complications, in undercorrection group (mean correction 27.24 %) it achieved 63.39 %. In the group of patients with vertebra arch penetration and pain syndrome the mean correction by universal endocorrector was 34.29 % with 100 % reduction of pain. During the 6–24 months follow- up there were no correction loss or neurologic and septic complications in operated patients. Conclusions. The new instrumentation provides greater correction (1.8 times) of scoliotic deformity than Harrington rod instrumentation. It is successfully used in repeat surgery and equally effective both in adolescent and in adult scoliosis.

Mechanical Modulation of Vertebral Growth in the Fusionless Treatment of Progressive Scoliosis in an Experimental Model

Wedging of apical spinal segments was measured during creation and correction of an experimental scoliosis in a goat model. To create and correct apical vertebral wedge deformities in a progressive experimental scoliosis model by purely mechanical means. The creation and correction of vertebral wedge deformities has been previously described in a rat tail model using external fixation. Experimental scoliosis was created in 14 goats using a posterior asymmetric tether with convex rib resection and concave rib tethering. After a period of up to 13 weeks, all tethers were removed and goats were randomized into treated (n = 8) and untreated (n = 6) groups. Treated goats underwent anterior thoracic stapling with four shape memory alloy staples along the convexity of the maximal curvature. Goats were followed for an additional 7 to 13 weeks during treatment. Serial radiographs were used to document progression or correction of the maximal scoliotic deformity as well as to measure the wedging of the apical spinal segment (two adjacent vertebrae and the intervening disc). During the tethering period, all goats achieved a progressive, structural, lordoscoliotic curve of significant magnitude (mean: 61 degrees, range: 49 to 73 degrees). Wedging of the apical spinal segment measured 11.1 degrees at the beginning and 22.4 degrees at the end of the tethering period. The increase in apical spinal segment wedging of +11.3 degrees (10.7 degrees vertebral/0.6-degree disc) was significant (P = 0.001). During the treatment period, the scoliosis in the stapled goats measured 56.8 degrees at the beginning and 43.4 degrees at the end for an average correction of -13.4 degrees (range: 0 to-22 degrees) (P = 0.001), whereas the untreated goats measured 67.0 degrees at the beginning and 59.8 degrees at the end for an average correction of -7.2 degrees (range: +7 to -21 degrees) (P = 0.19). Additionally, wedging of the apical spinal segment in the stapled goats measured 22.5 degrees at the beginning and 20.3 degrees at the end for an average correction of -2.2 degrees (-0.6 degrees vertebral/-1.6-degree disc); wedging of the apical vertebral segment in the untreated goats measured 22.3 degrees at the beginning and 25.8 degrees at the end of the treatment period for an average progression of +3.5 degrees (3.5 degrees vertebral/0.0-degree disc). The difference in apical spinal segment correction versus progression in the stapled (-2.2 degrees) versus control (+3.5 degrees) goats was significant (P < 0.05). This study demonstrates the ability to create wedge deformities at the apex of an experimental scoliosis in a large animal model and to control the progression of these deformities using anterior thoracic staples.

Die präoperative Halo-Extension bei hochgradiger Lähmungsskoliose

During the past decades the treatment of severe paralytic scoliosis has developed towards surgical treatment. However there is controversial discussion about the need of pre-operative Halo-traction. The aim of this study was to built two groups of patients -- one group with and another one without pre-operative Halo-traction -- and to compare the results after surgical correction of scoliotic deformity with data from literature. Between 2000-2003 twenty-five patients with severe neuromuscular spine deformity were treated surgically. Eight patients had preoperative Halo-traction, seventeen patients underwent directly operative correction and instrumentation. The evaluation included the pre- and postoperative X-rays as well those after Halo-traction before surgery. In the group without Halo-traction the scoliotic angle according to Cobb was reduced from 77 degrees to 33 degrees on average (mean correction of 44 degrees [57 %]). In the group with Halo-traction scoliosis was reduced from 85 degrees to 33 degrees on average (mean correction of 52 degrees [61 %]). The preoperative Halo-traction in patients with severe neuromuscular scoliosis indeed leads to radiologically higher correction, but this is not significant (p = 0.19) and only in single cases clinically relevant. In our point of view except from specific indications Halo-traction should not be applied in general as a standard procedure.

Optimization of Rib Surgery Parameters For the Correction of Scoliotic Deformities Using Approximation Models

As opposed to thoracoplasty (a cosmetic surgical intervention used to reduce the rib hump associated with scoliosis), experimental scoliosis has been produced or reversed on animals by rib shortening or lengthening. In a prior work (J. Orthop. Res., 20, pp. 1121-1128), a finite element modeling (FEM) of rib surgeries was developed to study the biomechanics of their correction mechanisms. Our aims in the present study were to investigate the influence of the rib surgery parameters and to identify optimal configurations. Hence, a specific objective of this study was to develop a method to find surgical parameters maximizing the correction by addressing the issue of high computational cost associated with FEM. Different configurations of rib shortening or lengthening were simulated using a FEM of the complete torso adapted to the geometry of six patients. Each configuration was assessed using objective functions that represent different correction objectives. Their value was evaluated using the rib surgery simulation for sample locations in the design space specified by an experimental design. Dual kriging (interpolation technique) was used to fit the data from the computer experiment. The resulting approximation model was used to locate parameters minimizing the objective function. The overall coverage of the design space and the use of an approximation model ensured that the optimization algorithm had not found a local minimum but a global optimal correction. The interventions generally produced slight immediate modifications with final geometry presenting between 95-120% of the initial deformation in about 50% of the tested cases. But in optimal cases, important loads (500-2000 N mm) were generated on vertebral endplates in the apical region, which could potentially produce the long-term correction of vertebral wedging by modulating growth. Optimal parameters varied among patients and for different correction objectives. Approximation models make it possible to study and find optimal rib surgery parameters while reducing computational cost.

Efficacy Assessment of One-Step Surgical Correction of Scoliotic Spine Deformity Using Cotrel-Dubousset Instrumentation

In 50 patients with dysplastic scoliosis (mobile deformity of III-IV degree) that underwent dorsal correction and spine fixation using Cotrel-Dubousset the mean postoperative correction of primary arch was equal 59.8%. Instrumental correction exceeded natural spine mobility average by 1.5 times. No significant segmental vertebrae derotation after surgical treatment was obtained. Postoperatively correct anatomic correlations of body and disk height on convex and concave deformity sides were restored. In further it was the determinant factor in preserving of achieved correction. The score system for the assessment of surgical scoliotic deformity correction was suggested. It allows presenting complex standardized characteristic of surgical treatment quality.

A three-dimensional radiographic comparison of Cotrel-Dubousset and Colorado instrumentations for the correction of idiopathic scoliosis.

A prospective clinical study comparing two instrumentation systems for the correction of idiopathic scoliosis. To measure the short-term three-dimensional changes in the shape of the spine after corrective surgery and compare the Cotrel-Dubousset instrumentation to the more recent Colorado instrumentation to determine whether one system provides better three-dimensional correction. Adequate three-dimensional correction of scoliotic deformities has been reported with the Cortrel-Dubousset instrumentation system. During the past decade, a new generation of more versatile and user-friendly spinal implants has appeared, but there are no reports available to indicate whether similar or better correction can be obtained with these newer systems. The three-dimensional geometry of the thoracic and lumbar spine was documented in the standing position using a three-dimensional reconstruction technique based on multiplanar radiography in 67 adolescents with idiopathic scoliosis undergoing correction by a posterior approach. Changes in spinal shape were measured 3 days before and 1 month after the surgery in 31 patients with Cotrel-Dubousset instrumentation and 36 patients with Colorado instrumentation. In both groups, adequate three-dimensional correction of the scoliotic deformities was documented for thoracic and lumbar curves, with significant changes in the frontal plane, in the plane of maximum curvature, and in its orientation. When comparing both groups, better correction was obtained in the frontal plane with the Colorado instrumentation (65% vs. 48% with Cotrel-Dubousset), a finding that may be explained by the significantly greater proportion of pedicle screws used in this group. Both instrumentation techniques achieve an effective and comparable three-dimensional correction of the scoliotic deformities.

Boston brace treatment vs simulation of a new orthotic approach for the correction of scoliotic deformities

Boston brace treatment vs simulation of a new orthotic approach for the correction of scoliotic deformities

Outcome of scoliotic deformity correction with Harrington distractor in adults

The results of surgical treatment of 36 patients with scoliosis, aged 18-29, were presented. Correction by Harrington distractor and posterior spondylosyndesis with allografts was performed. The average deformity correction achieved made up 38,8% of the initial value. Long term results (from 2 to 9 years) were studied in 29 patients. In 2 patients, complete loss of the correction was noted. In the rest of patients, the final correction varied from 9,9 to 49%, average 25,7%, of the initial value. The less is the scoliosis degree and age of a patient, the better is outcome of surgical correction. The preoperative pain syndrome being present in 7 patients was eliminated after operation.

特発性側わん症の手術成績 Ｈａｒｒｉｎｇｔｏｎ ｉｎｓｔｒｕｍｅｎｔａｔｉｏｎとＨａｒｒｉｎｇｔｏｎ＋ｓｅｇｍｅｎｔａｌ ｓｐｉｎａｌ ｉｎｓｔｒｕｍｅｎｔａｔｉｏｎの比較

We retrospectively reviewed the records of posterior arthrodesis for idiopathic scoliosis. Thirty patients had one stage posterior spinal arthr-odesis between 1971 and 1988 using one of types of instrumentation; a Harrington distraction rod, Harrington distraction and compression rods, Harrington distraction and compression rods with a device for transverse traction and a Harrington distraction rod with sublaminar wires.H. S. S. I. provides usefulness for rigid fixation and correction of scoliotic deformities compared with the conventional H. I..But no significant difference was found among another three groups.The use of a straight Harrington rod reduced normal thoracic Kyphosis, but the use of bending Harrington rod and S. S. I corrected thoracic hypoky-phosis.

せき柱側わん症に対するＨａｒｒｉｎｇｔｏｎ ｒｏｄ Ｓｅｇｍｅｎｔａｌ Ｓｐｉｎａｌ Ｉｎｓｔｒｕｍｅｎｔａｔｉｏｎ

Scoliosis treatment should be considered not only in a frontal plane but in a saggital. Herein the authors reported four scoliotic patients with loss of thoracic kyphosis successfully treated by Harrington rod Segmental Spinal Instrumentation (H-SSI).H-SSI provides a lot of advantages and usefullness for rigid fixation and correction of scoliotic deformities compared with the conventional Harrington Instrumentation, though it has technical difficulties with a high risk of complication.

Staged Correction of Neuromuscular Scoliosis

Anterior release and fusion, combined with tong gravity traction and second stage L-rod instrumentation, establishes correctability and accomplishes circumferential arthrodesis of the spine in neuromuscular scoliosis. From March 1979 through April 1982, nine patients with neuromuscular scoliosis, with an average age of 16.4 years, underwent this two-stage surgical procedure. The parameters investigated included correction of scoliotic deformity, correction of pelvic decompensation, and spinal arthrodesis. The preoperative scoliotic curvature measured 81 degrees and the postoperative curve measured 29.3 degrees, an average correction of 63.8%. Pelvic obliquity was significant in five of nine patients, averaging 36.2 degrees preoperatively. Postoperatively the pelvic obliquity averaged 11.8 degrees, an average correction of 67.4%. One of two pelvic fixation rods rotated out of the pelvis of one patient; roentgenographically he appears to have fused without loss of correction. A second patient has a poor fusion mass by roentgenographic criteria, although she has lost no correction and has had no pain. This technique offers results comparable to other series reporting arthrodesis for neuromuscular scoliosis. It has the advantages of requiring no anterior instrumentation and no postoperative immobilization.

Segmental Spinal Instrumentation for Correction of Scoliosis

Sixty-five consecutive scoliosis patients, 25 with idiopathic deformities and 40 with postpoliomyelitis deformities, were treated by preoperative correction, segmental spinal instrumentation with arthrodesis, and no postoperative immobilization. The follow-up ranged from 12 to 25 months (average, 18 months); no patients was lost to follow-up. The initial deformity varied from 35 degrees to 140 degrees (average, 69 degrees), and the final correction varied from 53% to 93% (average, 72%). The average loss of correction was 1.5 degrees, or 2%. The complications in this group were two infections and two pseudoarthroses. The author believes that segmental spinal instrumentation gives a planned maximum correction of scoliotic deformities, provides a satisfactory method of rigid internal fixation of the spine that needs no external fixation, and leads to rapid efficient arthrodesis.

Muscle Forces in the Posterior Thoracic Spine

Using a three-dimensional model, the theoretical maximal forces that can be generated by electrical stimulation of several posterior thoracic muscles have been analyzed to investigate the kinesiology of scoliosis. None provides a pure lateral bending moment, and most exaggerate lordosis. None satisfactorily generates a rotary force for correction of scoliotic deformity. Although maximum muscle contraction can ideally produce lateral bending moments of the same magnitude as the Milwaukee brace, current techniques do not cause continuous, complete muscle contraction. The best muscle studied for electrospinal intrumentation is the lateral erector spinae. Multiple sites of stimulating electrodes are probably necessary. None of the individual muscles studied is ideal. Further investigation should be directed to the stimulation of anterior thoracic muscles.

Spine jack operation in the correction of scoliotic deformity. A direct intrathoracic attack to straighten the laterally bent spine; preliminary report.

A direct intrathoracic method of treating scoliosis is described in which the laterally curved spine is straightened by a turnbuckle spine jack placed on the concave side of the curve. The jack is screw-fixed to an end vertebra proximally and distally before the turnbuckle is opened. Roentgenograms of the erect spine are taken before operation without traction and with halter traction, even to the point of full suspension of the patient. This indicates the traction elasticity response of the curve and spells out the resistance of the curved spine to any corrective force. The operation is done under intubation anesthesia and with blood transfusion to replace lost blood. The patient is placed on the operating table in the semiprone position with pillows under the knees. The knees are bent to a right angle. This position is held by adhesive strips which run over the buttocks to the table. He lies