Lumbar Adolescent Idiopathic Scoliosis Research Articles

Anterior Spinal Fusion for Thoraco-Lumbar Idiopathic Scoliosis Comparing Less Invasive Concave versus Traditional Convex Approach: A Pilot Study.

Background/Objectives: Anterior spinal fusion for primary thoracolumbar or lumbar (TL/L) adolescent idiopathic scoliosis, AIS, has advantages over posterior fusion, particularly in saving motion segments below the fusion construct. Traditionally, the approach is anterolaterally from the convexity. In adult degenerative scoliosis, the lateral or anterolateral approach may be performed from the traditional or from the concave approach which is less invasive and gives comparable outcomes. The purpose of the present pilot study was to assess the feasibility of the less invasive concave approach for younger AIS patients and compare it to the traditional convex approach over a 5-year follow-up period. Methods: The two cohorts were assessed by comparing pre- to postoperative radiographs, and clinical outcomes for pain, function, self-perception of appearance, and opinion of surgical success were prospectively obtained. Results: Radiographs found that primary TL/L scoliosis significantly improved from 53° to 18° (65%) for both the concave and convex cohorts. Sagittal alignments remained stable and there was no difference between cohorts. Coronal balance improved in both cohorts and sagittal balance was stable for both. Clinically, VAS back pain improved significantly for both cohorts initially and remained improved in the concave group. Leg pain, pain drawing, ODI disability, and VAS appearance scores improved and there was no difference between cohorts. The self-rating of success of the procedure was 100% at early and late follow-up periods. There were no neurological/surgical complications. Conclusions: The concave approach for anterior fusion for TL/L AIS is feasible with comparable radiographic and clinical outcomes to the traditional approach.

Incidence of Cervical Kyphosis and Factors Associated with Improvement in Postoperative Cervical Spinal Alignment in Idiopathic Scoliosis with Major Thoracolumbar/Lumbar and Thoracic Curves.

Background: This study aimed to compare the incidence and severity of cervical kyphosis before and after surgery between patients with adolescent idiopathic scoliosis (AIS) with major thoracolumbar/lumbar curves (Lenke type 5C group) and those with major thoracic curves (Lenke type 1A group). Further, factors associated with cervical spinal alignment changes after surgery in the two groups were examined. Methods: This study included consecutive patients with AIS who underwent posterior spinal fusion for Lenke type 1A and 5C curves and who were followed up for at least 1 year. To measure changes in sagittal alignment, all patients underwent radiography before, immediately after, and at 1 year after surgery. The correlation coefficients change the value of the C2-C7 angle before and after surgery (ΔC2-ΔC7) and other spinopelvic parameters were examined. Results: In total, 19 of 30 patients in the Lenke type 1A group and 21 of 36 in the Lenke type 5C group presented with cervical kyphosis preoperatively. Hence, the incidence of cervical kyphosis did not significantly differ between the two groups. Further, the two groups had significantly higher thoracic kyphosis (TK) and greater C2-C7 angles postoperatively. The TK of the Lenke type 5C group further increased at 1 year postoperatively. The Lenke 1A type group presented with a significant re-decrease in the C2-C7 angle at 1 year postoperatively. However, the C2-C7 angle of the Lenke type 5C group did not change. The ΔTK was closely associated with the ΔC2-ΔC7 in the Lenke type 1A group, but not in the Lenke type 5C group. Conclusions: In thoracic AIS, postoperative cervical alignment should achieve an adequate TK and promote correction of the coronal plane curve. Moreover, selective corrective surgery can improve postoperative cervical alignment in lumbar AIS.

Evaluation of Chêneau brace in the treatment of thoracic and lumbar adolescent idiopathic scoliosis with apical vertebral rotation.

Adolescent idiopathic scoliosis (AIS) is a common structural disorder of the spine in adolescents, often associated with structural deformities in both coronal and axial positions. Apical vertex rotation (AVR) is one of the main indicators of axial deformity in patients with scoliosis. Currently, there are few studies on the impact of AVR in the treatment of AIS. This study examined the influence of different AVR on AIS after brace treatment. Data were collected from 106 AIS participants aged 11-16 years from the orthopedic outpatient clinic of the Second Hospital of Lanzhou University. Two orthopaedic professionals measured the Cobb angle, AVR and spinal mid-line offset before and after brace treatment, and descriptive and linear correlation analyses were used to determine the correlation between AVR and AIS measured parameters. (1) In AIS volunteers with the same AVR, the treatment effect of AIS with lumbar predominant curvature was higher than that of AIS with thoracic predominant curvature. The treatment effect tended to decrease with increasing AVR. (2) Spinal mid-line deviation was associated with AVR. For patients with AIS with I and II degrees of AVR, the treatment effect of spinal mid-line offset after bracing is better. For AIS patients with AVR III degrees and above, the degree of correction of spinal mid-line offset decreases with the continuous correction of Cobb angle. The efficacy of AIS was found to be related to the severity of AVR. The efficacy of AIS with predominantly lumbar curvature was significantly higher than that of AIS with predominantly thoracic curvature. The efficacy of treatment of mid-line spinal deviation also decreased with increasing AVR.

Posterior-only correction surgery for idiopathic scoliosis Lenke type 5c: differences of strategies and outcomes between adult patients and adolescent patients

PurposeTo compare radiographic parameters, and functional and surgical outcomes between lumbar adolescent idiopathic scoliosis (AIS) and lumbar adult idiopathic scoliosis (AdIS).MethodsA retrospective study was performed to identify Lenke 5c type AIS and AdIS patients from our scoliosis database who had undergone posterior surgical treatment for scoliosis. Preoperative and postoperative radiographic and clinical outcomes were compared between the two groups.ResultsA total of 22 patients were included in AdIS group, and 44 matched patients in AIS group. AdIS group had significantly larger L3 and L4 tilt and translation than AIS group (P < 0.05). AdIS group had larger T10-L2 angle and smaller T5–T12 angle (P < 0.05). AdIS group had higher VAS scores (P < 0.05) and pain domain of SRS-22 scores (P < 0.05) as compared to AIS group. Correlation analysis demonstrated positive relationship between VAS scores and T10-L2 angle (r = 0.492, P < 0.05). AdIS group was fused longer than AIS group (P < 0.05). Cobb angle of TL/L curve was larger and correction ratio was smaller at AdIS group (P < 0.05). AdIS group still had significantly larger L3 and L4 tilt and translation than AIS group (P < 0.05). CT measurements demonstrated larger postoperative vertebral body rotation at apical vertebrae and LIV at AdIS group (P < 0.05). Vertebral correction ratio was smaller at AdIS group (P < 0.05).ConclusionLenke 5c AdIS patients had greater preoperative and postoperative L3 and L4 tilt and translation, as well as less correction of major curve and vertebral body derotation than AIS patients. However, the incidence of adding-on was similar between the two groups.

The role of sagittal pelvic morphology in the development of adult degenerative scoliosis

PurposePelvic morphology dictates the alignment and biomechanics of the spine. Recent observations in different types of adolescent idiopathic scoliosis indicate that individual pelvic morphology is related to the spinal levels in which scoliosis develops: primary lumbar adolescent scoliosis is associated with a higher pelvic incidence (PI) than thoracic scoliosis and non-scoliotic controls. We hypothesize that adult degenerative scoliosis (ADS) of the lumbar spine follows the same mechanical principles and is associated with a high PI.MethodsThis study used an existing CT-scan database, 101 ADS patients were sex and age matched to 101 controls. The PI was measured by two observers with multi-planar reconstruction, perpendicular to the hip-axis according to a previously validated technique.ResultsThe PI was 54.1° ± 10.8° in ADS patients and 47.7° ± 10.8° in non-scoliotic controls (p < 0.001). The median ADS curve apex was the disc L2-3 and median curve length was 4 vertebral levels. The mean supine Cobb angle was 21° ± 8° (ranged 10°–47°). There was no significant correlation between PI and the apex level (p = 0.883), the curve length (p = 0.418) or the Cobb angle (p = 0.518).ConclusionsADS normally develops de novo in the lumbar spine of patients with a higher PI than controls, similar to primary lumbar adolescent idiopathic scoliosis. This suggests a shared mechanical basis of both deformities. Pelvic morphology dictates spinal sagittal alignment, which determines the segments of the spine that are prone to develop scoliosis.

Isometric Yoga-Like Maneuvers Improve Adolescent Idiopathic Scoliosis-A Nonrandomized Control Trial.

ObjectiveAssess therapeutic value of specific yoga poses for thoracic and lumbar adolescent idiopathic scoliosis (AIS) taught in office or Internet.Study DesignNonrandomized control trial: Fifty-six adolescents (mean age 14.0 years; mean Risser 3.0) were recruited from our clinic; 41 did the side-plank, the half-moon and elevated side plank poses as appropriate (treatment group) and 15 did not (controls). Thirty curves were treated in office, 30 via Internet. Curve change was evaluated by blinded serial Cobb angles, and analyzed using Mann-Whitney U, paired t-tests and χ2.ResultsMean lumbar and thoracolumbar Cobb angle change was −9.2 (95% CI = −11.8, −6.6) in the treatment group and 5.4 (95% CI = 1.7, 9.0) in controls. Both treatment group improvement and deterioration in controls were significant (treatment group: paired t-test t = −7.1, df = 40, p = .000; controls: t = 3.2, df = 12, p = .008). Mean thoracic Cobb angle change was −7.1 (95% CI = −13.1, −1.2) in the treatment group and 9.3 (95% CI = 4.5, 14.6) in controls. Both changes were significant (paired t-test t = −3.3, df = 21, p = .022 for treatment group; t = 4.5, df = 5, p = .006 for controls). Nine Internet patients were non-compliant vs. 6 office patients. Office patients improved 1.6 degrees/month or 5.5%/month; Internet patients improved .72 degrees/month or 3.3%/month.ConclusionThese yoga poses show promise for reversing adolescent idiopathic scoliosis. Telemedicine had greater non-compliance and lower efficacy but still produced patient improvement.

How to Avoid Distal Adding-on Phenomenon for Rigid Curves in Major Thoracolumbar and Lumbar Adolescent Idiopathic Scoliosis? Identifying the Incidence of Distal Adding-on by Selection of Lowest Instrumented Vertebra

We sought to compare the radiologic outcomes for different distal fusion levels in a rigid curve with major thoracolumbar and lumbar (TL/L) adolescent idiopathic scoliosis (AIS) using rod derotation (RD) with direct vertebral rotation (DVR) after pedicle screw instrumentation (PSI). This study finally enrolled 28 patients who were diagnosed with AIS in rigid curve with major TL/L curves, treated by PSI with RD and DVR and with a minimum 2-year follow-up. Patients were divided into 2 groups, L3 and L4, on the basis of the distal fusion level at the lowest instrumented vertebra (LIV) of L3 or L4. There was no significant difference in TL/L curve, thoracic (minor), and compensatory (caudal) curves between the L3 and L4 groups either postoperatively (P= 0.162, 0.426, and 0.762, respectively) or at the last follow-up (P= 0.952, 0.620, and 0.562, respectively). The overall prevalence of unsatisfactory results was 42.9% (12/28 patients). The prevalence of unsatisfactory results was 61.1% (11/18) in the L3 group and 10% (1/10) in the L4 group, which was significantly different (P < 0.05). Unsatisfactory results occurred more often in the L3 group than in the L4 group, and unsatisfactory results had significant influence on progression of TL/L and distal compensatory curves. Such progression was closely correlated with deteriorating LIV disk angle in the L3 group. Therefore if the curve is rigid, LIV should be extended to L4 to avoid the adding-on phenomenon in the treatment of major TL/L AIS using RD with DVR after PSI.

Comparison of Pulmonary Function After Selective Anterior Versus Posterior Fusion for the Correction of Thoracolumbar and Lumbar Adolescent Idiopathic Scoliosis.

Study Design:Retrospective multicenter study.Objectives:To compare the selective anterior spinal fusion (ASF) versus posterior spinal fusion (PSF) on postoperative pulmonary function testing (PFT) whether thoracotomy with separation of the diaphragm by anterior approach influences the PFT in thoracolumbar and lumbar adolescent idiopathic scoliosis (AIS).Methods:A multicenter series of AIS patients who underwent selective spinal fusion were retrospectively reviewed. Seventy-nine female patients were included (mean 15.8 years). There were 35 patients in the ASF group and 44 patients in the PSF group. Patient demographics, radiographic measurements, and PFT data from preoperative to 2-year follow-up were analyzed.Results:Preoperatively, there were no significant differences in PFTs between the groups. The ASF group patients were more likely to undergo shorter fusions (4.5 instrumented vertebral levels) than those in the PSF group (5.2 levels). At 2-year follow-up, forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1) in ASF group were statistically lower than those in PSF group. When comparing preoperative and 2-year changes on each procedure, only %FVC showed significant difference in ASF while FVC, FEV1, and %FEV1 did not. Meanwhile, the ASF group showed a significant decrease in FVC at 6 and 12 months compared to preoperative values. In PSF group, there was a decrease at 6 months, returned to preoperative value at 1-year follow-up.Conclusions:Pulmonary function after ASF and PSF was similar at 2 years; however, anterior group did not return to the baseline at 6 months and 1 year suggesting anterior approach may affect early postoperative pulmonary function.

A hierarchical classification of adolescent idiopathic scoliosis: Identifying the distinguishing features in 3D spinal deformities.

This study aimed to identify the differentiating parameters of the spinal curves’ 2D projections through a hierarchical classification of the 3D spinal curve in adolescent idiopathic scoliosis (AIS). A total number of 103 right thoracic left lumbar pre-operative AIS patients were included retrospectively and consecutively. A total number of 20 non-scoliotic adolescents were included as the control group. All patients had biplanar X-rays and 3D reconstructions of the spine. The 3D spinal curve was calculated by interpolating the center of vertebrae and was isotropically normalized. A hierarchical classification of the normalized spinal curves was developed to group the patients based on the similarity of their 3D spinal curve. The spinal curves’ 2D projections and clinical spinal measurements in the three anatomical planes were then statistically compared between these groups and between the scoliotic subtypes and the non-scoliotic controls. A total of 5 patient groups of right thoracic left lumbar AIS patients were identified. The characteristics of the posterior-anterior and sagittal views of the spines were: Type 1: Normal sagittal profile and S shape axial view. T1 is leveled or tilted to the right in the posterior view. Type 2: Hypokyphotic and a V shape axial view. T1 is tilted to the left in the posterior view. Type 3: Hypokyphotic (only T5-T10) and frontal imbalance, S shape axial view. T1 is leveled or tilted to the right, and 3 frontal curves. Type 4: Flat sagittal profile (T1-L2), slight frontal imbalance with a V shape axial view, T1 tilted to the left. Type 5: flat sagittal profile and forward trunk shift with a proximal kyphosis and S shape axial view. T1 is leveled or tilted to the right. In conclusion, a hierarchical classification of the 3D scoliotic spine allowed identifying various distinguishing features of the spinal curves in patients with a right thoracic curve in an orderly fashion. The subtypes’ characteristics resulting from this 3D classification can be identified from the pairs of the frontal and sagittal spinal curves i.e. X-rays in right thoracic AIS patients.

Sagittal Profile Response of Cervical Spine After Posterior Correction in Thoracic and Lumbar Adolescent Idiopathic Scoliosis: Correlation with Thoracic Kyphosis?

To analyze postoperative changes in cervical alignment in patients with adolescent idiopathic scoliosis (AIS) with different curve patterns. Radiographic data were retrospectively reviewed in 43 patients with AIS with right thoracic major curve versus 39 with major lumbar curve with a minimum of 2 years' follow-up. Radiographic parameters analyzed in this study included cervical sagittal parameters (cervical lordosis [CL], T1 slope, T1 slope minus C2-C7 lordosis, T1-spine, T1 pelvic angle, and C2-C7 sagittal vertical axis) and spinopelvic sagittal parameters obtained from radiographs. Paired t tests were used for comparison with 0.05 as a statistically significant threshold. At baseline, larger CL (5.69° vs.-5.12°, P= 0.002) and smaller T1 slope minus C2-C7 lordosis (9.26° vs. 17.09°, P= 0.001) was noted in patients with lumbar-curve adolescent idiopathic scoliosis (L-AIS), whereas preoperative thoracic kyphosis (TK) was not different between the 2 groups. When the immediate postoperative sagittal profiles were compared between the 2 groups, larger TK (23.72° vs. 18.86°, P= 0.009) and more obvious CL (7.26° vs.-2.60°, P= 0.001) were noticed in the L-AIS group. During the follow-up, larger TK and CL were still maintained in the L-AIS group. In addition, a significant correlation was found between the improvement of CL and TK restoration in patients with L-AIS (r=-0.473, P= 0.002). Correlations between the improvement of CL and TK highlight the importance of restoration of patients with normal TK or AIS. Reciprocal changes in cervical alignment may happen if the TK was also simultaneously restored in patients with AIS. For patients with different curve patterns, the cervical sagittal parameters tend to be similar during follow-up.

Anterior-posterior length discrepancy of the spinal column in adolescent idiopathic scoliosis—a 3D CT study

Background ContextOne of the characteristics of reported observations in adolescent idiopathic scoliosis (AIS) is that the thoracic spine is longer anteriorly than posteriorly, more pronounced around the apex than the transitional zones. This reversal of the normal kyphotic anatomy of the thoracic spine is related to questions of etiopathogenesis of AIS. The changes in the anatomy of the anterior column have been described rather in detail; however, the role of the posterior spinal column and the laminae has so far not been elucidated. If the posterior column exhibits a longitudinal growth disturbance, it could act as a tether, leading to a more or less normal anterior column with a deformed and shorter posterior aspect of the spine. So far, it has remained unclear whether this anterior-posterior length discrepancy is the result of relative anterior lengthening or relative posterior shortening, and which tissues (bone, disc, intervertebral soft tissue) are involved. PurposeThe present study aimed to compare the discrepancy of the anterior-posterior length of the spinal column in the “true” midsagittal plane of each vertebra in patients with idiopathic scoliosis versus controls, using three-dimensional computed tomography (CT) scans. Study Design/SettingThis is a cross-sectional study. Patient SampleThe sample consisted of computed tomography scans of 80 patients with moderate to severe AIS (Cobb angle: 46°–109°) before scoliosis navigation surgery and 30 non-scoliotic age-matched controls. Outcome MeasuresThe height of the osseous and non-osseous structures from anterior to posterior in the “true” midsagittal plane has been determined: the anterior side of the vertebral body and disc, the posterior side of the vertebral body and disc, the lamina and interlaminar space and the spinous process and interspinous space, as well as the height ratios between the anterior column and posterior structures of the primary thoracic and lumbar AIS curves and corresponding levels in non-scoliotic controls. MethodsSemiautomatic software was used to reconstruct and measure the parameters in the true midsagittal plane of each vertebra and intervertebral structure that are rotated and tilted in a different way. ResultsIn AIS, the anterior height of the thoracic curve was 3.6±2.8% longer than the posterior height, 2.0±6.1% longer than the length along the laminae, and 8.7±7.1% longer than the length along the spinous processes, and this differed significantly from controls (−2.7±2.4%, −7.4±5.2%, and +0.7±7.8%; p<.001). The absolute height of the osseous parts did not differ significantly between AIS and controls in the midsagittal plane. In contrast, the intervertebral structures contributed significantly to the observed length discrepancies. In absolute lengths, the anterior side of the disc of the thoracic curve was higher in AIS (5.4±0.8 mm) than controls (4.8±1.0 mm; p<.001), whereas the interspinous space was smaller in AIS (12.3±1.4 mm vs. 14.0±1.6 mm; p<.001). ConclusionsBased on this in vivo analysis, the true three-dimensional anterior-posterior length discrepancy of AIS curves was found to occur through both anterior column lengthening and posterior column shortening, with the facet joints functioning as the fulcrum. The vertebrae contribute partly to the anterior-posterior length discrepancy accompanied by more significant and possibly secondary increased anterior intervertebral discs height.

Genetic Variant of SOCS3 Gene is Functionally Associated With Lumbar Adolescent Idiopathic Scoliosis.

This is a genetic association study. To investigate association between suppressor of cytokine signaling-3 (SOCS3) gene polymorphisms and the onset and progression of lumbar adolescent idiopathic scoliosis (AIS) and to further clarify its role in the regulation of SOCS3 expression in AIS patients. Some studies showed that muscle development imbalance may be responsible for onset and progression of lumbar AIS. SOCS3 is one of the significant regulators of skeletal muscle development, and in vitro study showed that SOCS3 influences myoblast differentiation. Rs4969198 was genotyped in 476 lumbar AIS patients and 672 controls. The differences of genotype and allele distributions between patients and controls were calculated using the χ test. Paravertebral muscles were collected from 53 AIS, 23 congenital scoliosis, and 18 lumbar disk herniation patients. AIS patients were classified into 3 groups according to the genotypes of each single nucleotide polymorphisms, and 1-way analysis of variance test was used to compare SOCS3 expression among different groups and genotypes. Patients were found to have a significantly higher frequency of GG than the controls (40.8% vs. 29.9%, odds ratio=1.36; P=0.000), and the frequency of allele G was found to be remarkably higher in the patients than the controls (65.3% vs. 56.7%, odds ratio=1.15; P=0.000). AIS patients had significantly less muscle expression of the SOCS3 than the congenital scoliosis patients (2.73±2.17 vs. 4.62±2.41; P=0.006) and the lumbar disk herniation patients (2.73±2.17 vs. 4.12±2.93; P=0.009). The SOCS3 expression was significantly correlated with the curve severity (r=0.472; P=0.014). The SOCS3 gene is significantly associated with the development of lumbar AIS in Chinese population. Decreased expression of SOCS3 is associated with larger severity of lumbar AIS. Level III.

Selection of Lowest Instrumented Vertebra in the Management of Thoracolumbar and Lumbar Adolescent Idiopathic Scoliosis using Pedicle Screw Instrumentation

Introduction The aim of surgical treatment for adolescent idiopathic scoliosis (AIS) is correction of the three dimensional deformity, achievement of stability and preservation of as many distal motion segments as possible. In Thoracolumbar/ Lumbar adolescent idiopathic scoliosis (TL/L AIS) correction of C-shaped coronal curve into S-shaped saggital curve is a considerable challenge to a spine surgeon. In this regard, selection of Lowest Instrumented Vertebra (LIV) is of particular importance and remains controversial in literature. We conducted a retrospective study involving Lenke V patients to determine the exact distal fusion level (LIV) in the management of thoracolumbar/lumbar adolescent idiopathic scoliosis (TL/L AIS) using pedicle screw instrumentation. Material and Methods Analysis of radiographic parameters of 32 TL/L AIS was done. The patients were grouped according to the Lowest Instrumented Vertebra; Group I (fusion to L3, n = 25) and Group II (fusion to L4, n = 7). The Group I was subdivided into Group IA (L3 crosses the mid-sacral line with rotation of less than grade II on bending films, n = 14) and Group IB (L3 does not cross the mid-sacral line or rotation is grade II or more on bending films, n = 11). All of the patients in the Group II had the same location and rotation of L3 in bending films as that of patients in the Group IB. Patients with lowest instrumented vertebral tilt (LIVT) of more than 10° or coronal balance of more than 15 mm were considered to have unsatisfactory results. Results In these 3 groups, there was a significantly lesser correction in the TL/L curve and LIVT in the Group IB. Unsatisfactory results were obtained in 1 patients (7.1%) of the Group IA, in 7 patients (63.3%) of the Group IB, and in 1 patient (12.5%) of the Group II, which was found to be statistically significant. Conclusion In TL/L AIS patients undergoing treatment with pedicular screw instrumentation, the curve can be fused to L3 with good radiographic outcomes when L3 crosses the mid-sacral line with rotation of less than grade II on bending films. Otherwise, L4 should be selected as the Lowest Instrumented Vertebra.

Decision making for upper instrumented vertebra in thoracolumbar/lumbar adolescent idiopathic scoliosis: can we stop below the end vertebra?

Sudo H, Kaneda K, Shono Y, Iwasaki N. Selection of the upper vertebra to be instrumented in the treatment of thoracolumbar and lumbar adolescent idiopathic scoliosis by anterior correction and fusion surgery using dual-rod instrumentation: a minimum 12-year follow-up study. Spine J. 2016:16:281-7 (in this issue).

Selection of the upper vertebra to be instrumented in the treatment of thoracolumbar and lumbar adolescent idiopathic scoliosis by anterior correction and fusion surgery using dual-rod instrumentation: a minimum 12-year follow-up study

BackgroundContextConsensus regarding the optimal upper vertebra to be instrumented during surgical treatment of Lenke 5C thoracolumbar and lumbar adolescent idiopathic scoliosis (AIS) remains limited. PurposeThis study aimed to assess whether a short fusion strategy is appropriate for correction of a Lenke 5C AIS curve by anterior correction and fusion surgery using dual-rod instrumentation. Study DesignThis study design used retrospective comparative analysis of a prospectively collected, consecutive, non-randomized series of patients at a single institution. Patient SampleThirty consecutive patients with Lenke 5C AIS treated with anterior correction and fusion surgery using dual-rod instrumentation were included. Outcome MeasuresPatient demographics, radiographic measurements, and Scoliosis Research Society-22 questionnaire (SRS-22) scores were the outcome measures for this study. MethodsThirty patients were treated surgically for AIS with a Lenke 5C curve (mean age, 14.4 years [11–19 years)]) and followed up for a mean period of 17.2 years (12–23 years). Radiographical parameters and clinical outcomes were compared between patients treatment with the end vertebra (EV) instrumented (n=14) and those treated by short fusion (S group) with instrumentation starting at the vertebra one level caudal to the EV (n=16 patients). There were no study-specific biases related to conflicts of interest. ResultsIn the EV group, a mean preoperative Cobb angle of 56° was corrected to 5° after surgery and to 8° at the final follow-up. In the S group, a mean preoperative Cobb angle of 55° was corrected to 10° after surgery and 14° at the final follow-up. The mean correction rate at the final follow-up was significantly lower in the S group (74%) than in the EV group (86%; p=.020). The coronal and sagittal balance, thoracic kyphosis, lumbar lordosis, and clinical outcomes evaluated using SRS-22 did not differ between the two groups. ConclusionsThe short fusion strategy, which involves instrumentation of the vertebra one level caudal to the upper EV, can be considered as an alternative to the conventional strategy, which includes instrumentation of the upper EV, for treating Lenke 5C curves via anterior spinal fusion.

Adult scoliosis: age-related deformity and surgery.

We retrospectively analyzed our results in thoracolumbar and lumbar adolescent idiopathic scoliosis treated during adulthood. Fifty-two thoracolumbar and 30 lumbar idiopathic scoliosis surgically treated were reviewed. Mean follow-up was 9.5±6.6years. All the subjects were analyzed by visual analog scale, Oswestry Disability Index (ODI), and SF-36 scores before and after surgery and at follow-up. The scoliotic curve, thoracic kyphosis, lumbar lordosis, pelvic incidence (PI), pelvic tilt (PT), sacral slope, and C7 plumb line were measured. For the statistical analysis, multivariate multiple regression models were formulated, considering as significative a P<0.05. A statistically significant clinical and radiological amelioration was noted after surgery and at final follow-up. According to the logistic regression model, ODI was related to lumbar lordosis and spino-pelvic parameters at follow-up. The only determinant of failure was age. Spino-pelvic recovery is easier in patients aged less than 60years with PI<55° and PT<25°.

Differences in early sagittal plane alignment between thoracic and lumbar adolescent idiopathic scoliosis

Background contextIt has previously been shown that rotational stability of spinal segments is reduced by posteriorly directed shear loads that are the result of gravity and muscle tone. Posterior shear loads act on those segments of the spine that are posteriorly inclined, as determined by each individual's inherited sagittal spinal profile. Accordingly, it can be inferred that certain sagittal spinal profiles are more prone to develop a rotational deformity that may lead to idiopathic scoliosis; and lumbar scoliosis, on one end of the spectrum, develops from a different sagittal spinal profile than thoracic scoliosis on the other end. PurposeTo examine the role of sagittal spinopelvic alignment in the etiopathogenesis of different types of idiopathic scoliosis. Study design/settingMulticenter retrospective analysis of lateral radiographs of patients with small thoracic and lumbar adolescent idiopathic scoliotic curves. Patients sampleWe included 192 adolescent idiopathic scoliosis patients with either a thoracic (n=128) or lumbar (n=64) structural curve with a Cobb angle of less than 20° were studied. Children with other spinal pathology or with more severe idiopathic scoliosis were excluded, because this disturbs their original sagittal profile. Subjects who underwent scoliosis screening and had a normal spine were included in the control cohort (n=95). Outcome measuresThoracic kyphosis, lumbar lordosis, T9 sagittal offset, C7 and T4 sagittal plumb lines, pelvic incidence, pelvic tilt, and sacral slope, as well as parameters describing orientation in space of each individual vertebra between C7 and L5 and length of the posteriorly inclined segment. MethodsOn standardized lateral radiographs of the spine, a systematic, semi-automatic measurement of the different sagittal spinopelvic parameters was performed for each subject using in-house developed computer software. ResultsEarly thoracic scoliosis showed a significantly different sagittal plane from lumbar scoliosis. Furthermore, both scoliotic curve patterns were different from controls, but in a different sense. Thoracic kyphosis was significantly decreased in thoracic scoliosis compared with both lumbar scoliosis patients and controls. For thoracic scoliosis, a significantly longer posteriorly inclined segment, and steeper posterior inclination of C7–T8 was observed compared with both lumbar scoliosis and controls. In lumbar scoliosis, the posteriorly inclined segment was shorter and located lower in the spine, and T12–L4 was more posteriorly inclined than in the thoracic group. The lumbar scoliosis cohort had a posteriorly inclined segment of the same length as controls, but T12–L2 showed steeper posterior inclination. Lumbar lordosis, pelvic incidence, pelvic tilt, and sacral slope, however, were similar for the two scoliotic subgroups as well as the controls. ConclusionsThis study demonstrates that even at an early stage in the condition, the sagittal profile of thoracic adolescent idiopathic scoliosis differs significantly from lumbar scoliosis, and both types of scoliosis differ from controls, but in different aspects. This supports the theory that differences in underlying sagittal profile play a role in the development of different types of idiopathic scoliosis.

Anterior surgery for adolescent idiopathic scoliosis

Anterior open scoliosis surgery using the dual rod system is a safe and rather effective procedure for the correction of scoliosis (50-60%). Thoracic hypokyphosis and rib hump correction with open anterior rather than posterior instrumentation appear to be the better approaches, although the latter is somewhat controversial with current posterior vertebral column derotation devices. In patients with Risser grade 0, hyperkyphosis and adding-on may occur with anterior thoracic spine instrumentation. Anterior thoracoscopic instrumentation provides a similar correction (65%) with good cosmetic outcomes, but it is associated with a rather high risk of instrumentation (pull-out, pseudoarthrosis) and pulmonary complications. Approximately 80% of patients with adolescent idiopathic scoliosis (AIS) curves of >70° have restrictive lung disease or smaller than normal lung volumes. AIS patients undergoing anterior thoracotomy or anteroposterior surgery will demonstrate a significant decrease in percentage of predicted lung volumes during follow-up. The thoracoabdominal approach and thoracoscopic approach without thoracoplasty do not produce similar changes in detrimental lung volume. In patients with severe AIS (>90°), posterior-only surgery with TPS provides similar radiographic correction of the deformity (44%) with better pulmonary function outcomes than anteroposterior surgery. Vascular spinal cord malfunction after segmental vessel ligation during anterior scoliosis surgery has been reported. Based on the current literature, the main indication for open anterior scoliosis instrumentation is Lenke 5C thoracolumbar or lumbar AIS curve with anterior instrumentation typically between T11 and L3.

Thoracic curve correction after posterior fusion and instrumentation of structural lumbar curves in patients with adolescent idiopathic scoliosis

Spontaneous thoracic curve correction may occur following selective anterior spinal fusion in patients with adolescent idiopathic scoliosis (AIS). However, a few reports have described outcomes in patients following selective posterior fusion. The aim of this retrospective study was to assess curve correction in AIS patients with major lumbar curves and secondary thoracic curves after selective posterior fusion of the major curve. The records of 42 AIS patients with major lumbar and minor thoracic curves who had received selective posterior lumbar fusion with segmental pedicle screw fixation were examined. Preoperative and follow-up radiographs were examined and the following were determined: curve flexibility, Cobb angle measurements of the major and minor curves, thoracolumbar/lumbar and thoracic Cobb measurements. Also, thoracolumbar/lumbar to thoracic Cobb ratios were determined. Minimum follow-up was 2 years. Patients were compared with respect to whether final thoracic curve improvement was (group A) or was not (group B) apparent. Improvement was indicated by a final thoracic curve that was less than the preoperative thoracic curve. Thoracic curve improvement was apparent in 32 of 42 patients after surgery. The mean preoperative thoracic curve in group A was 22.5° and 15.0° at follow-up, while corresponding values in group B were 35.0° and 39.8°. There were no cases in group A and eight cases in group B in which the preoperative thoracic curve was >30°. All patients in group B had preoperative thoracic curves on lateral bending >20°. Thoracic curvature at final follow-up was strongly correlated with preoperative thoracic curvature (r = 0.911) and thoracic curvature on lateral bending (r = 0.948). Selective posterior fusion with segmental pedicle screw fixation in patients with major lumbar AIS resulted in curve correction in the majority of cases. Preoperative thoracic curvature and thoracic curvature on lateral bending were strongly correlated with the final thoracic curvature.

Gait in adolescent idiopathic scoliosis: energy cost analysis

Walking is a very common activity for the human body. It is so common that the musculoskeletal and cardiovascular systems are optimized to have the minimum energetic cost at 4 km/h (spontaneous speed). A previous study showed that lumbar and thoracolumbar adolescent idiopathic scoliosis (AIS) patients exhibit a reduction of shoulder, pelvic, and hip frontal mobility during gait. A longer contraction duration of the spinal and pelvic muscles was also noted. The energetic cost (C) of walking is normally linked to the actual mechanical work muscles have to perform. This total mechanical work (W(tot)) can be divided in two parts: the work needed to move the shoulders and lower limbs relative to the center of mass of the body (COM(b)) is known as the internal work (W(int)), whereas additional work, known as external work (W(ext)), is needed to accelerate and lift up the COM(b) relative to the ground. Normally, the COM(b) goes up and down by 3 cm with every step. Pathological walking usually leads to an increase in W (tot) (often because of increased vertical displacement of the COM(b)), and consequently, it increases the energetic cost. The goal of this study is to investigate the effects of scoliosis and scoliosis severity on the mechanical work and energetic cost of walking. Fifty-four female subjects aged 12 to 17 were used in this study. Thirteen healthy girls were in the control group, 12 were in scoliosis group 1 (Cobb angle [Cb] < or = 20 degrees), 13 were in scoliosis group 2 (20 degrees < Cb < 40 degrees), and 16 were in scoliosis group 3 (Cb > or = 40 degrees). They were assessed by physical examination and gait analysis. The 41 scoliotic patients had an untreated progressive left thoracolumbar or lumbar AIS. During gait analysis, the subject was asked to walk on a treadmill at 4 km h(-1). Movements of the limbs were followed by six infrared cameras, which tracked markers fixed on the body. W(int) was calculated from the kinematics. The movements of the COM(b) were derived from the ground reaction forces, and W(ext) was calculated from the force signal. W(tot) was equal to W(int) + W(ext). Oxygen consumption VO2 was measured with a mask to calculate energetic cost (C) and muscular efficiency (W(tot)/C). Statistical comparisons between the groups were performed using an analysis of variance (ANOVA). The external work (W(ext)) and internal work (W(int)) were both reduced from 7 to 22% as a function of the severity of the scoliosis curve. Overall, the total muscular mechanical work (W(tot)) was reduced from 7% to 13% in the scoliosis patients. Within scoliosis groups, the W(ext) for the group 1 (Cb > or = 20 degrees) and 2 (20 < or = Cb < or = 40 degrees) was significantly different from group 3 (Cb > or = 40 degrees). No significant differences were observed between scoliosis groups for the W(int). The W(tot) did not showed any significant difference between scoliosis groups except between group 1 and 3. The energy cost and VO2 were increased by around 30%. As a result Muscle efficiency was significantly decreased by 23% to 32%, but no significant differences related to the severity of the scoliosis were noted. This study shows that scoliosis patients have inefficient muscles during walking. Muscle efficiency was so severely decreased that it could be used as a diagnostic tool, since every scoliosis patient had an average muscle efficiency below 27%, whereas every control had an average muscle efficiency above 27%. The reduction of mechanical work found in scoliotic patients has never been observed in any pathological gait, but it is interpreted as a long term adaptation to economize energy and face poor muscle efficiency. With a relatively stiff gait, scoliosis patients also limit vertical movement of the COM(b) (smoothing the gait) and consequently, reduce W(ext) and W(int). Inefficiency of scoliosis muscles was obvious even in mild scoliosis (group 1, Cb < 20 degrees) and could be related to the prolonged muscle contraction time observed in a previous study (muscle co-contraction).